When I'm on the night shift, all the department heads can't sleep.

Gao Yuan, who was wearing a black T-shirt, was stopped by Nurse Zhu's words and stopped in front of the triage desk.

When Nurse Zhu told him to sit back in the row of chairs on the outside, he glanced at the general outpatient area before explaining in a low voice, "I didn't mean to cut in line. My dad is still sitting over there waiting for his scans; he's hard of hearing and can't hear his number being called."

Nurse Zhu didn't let him continue standing at the counter: "Go back and sit down first. I'll have a nurse go and watch over your dad. Don't walk through the waiting area by yourself yet."

Gao Yuan took two steps back and sat back down on the outermost side of the chair.

The row of chairs near the triage desk originally housed seven or eight people. Upon hearing the words "38.7 degrees Celsius," Liu Yan, who was next to her, instinctively helped her mother move closer to her.

Nurse Zhu noticed this and said, "Don't change seats yet. Please sit down first. I'll check who in this row was in the CT waiting area just now."

Liu Yan immediately waved her hand: "Nurse, we're not related. I'm here with my mom for an X-ray. She's coughing, but I don't have a fever myself."

Du Zhiqiang, on the other end of the line, coughed twice and put his phone on his lap: "I don't know him either. I came here for a CT scan on my own, I didn't come with them."

"Even if you don't know them, please sit down." Nurse Zhu turned to the nurse next to her and said, "Bring some new masks over. No one else should come in from the outer row yet, and those who come later should not sit here."

Lin Ye looked at the examination report in Gao Yuan's hand. The name on the report was Gao Limin, 62 years old.

He walked to the side of the triage desk and opened the respiratory symptom registration book: "Where is your dad right now?"

"Outside the general outpatient area," Gao Yuan pointed. "He's been coughing for two or three days, and this afternoon his fever reached over 38 degrees Celsius. The doctor ordered a chest CT scan, and he just came back to wait for the results. I started feeling cold just outside the radiology department; I thought it was from the air conditioning."

Lin Ye first noted down the time: "When you accompanied him here, did you have a fever?"

"No, just a dry throat. My dad got a fever first, I felt unwell while waiting for the CT scan."

"How long did you wait outside the CT room?"

Gao Yuan thought for a moment: "About half an hour. There were a lot of people, and all the chairs were full. My dad was coughing a lot, and he took off his mask to drink water in the middle."

Nurse Zhu handed over the new masks, first letting Gao Yuan put one on, then handing them to Liu Yan and Du Zhiqiang: "You guys change too. Loose masks are prone to letting in drafts, so change into new ones first."

As Liu Yan adjusted her mother's mask, she muttered, "We were indeed waiting at the CT scan area. My mom was coughing a lot, and the doctor said they'd check after the scan."

Lin Ye glanced at the examination report she handed him. The patient's name was Feng Yuzhen, and the person accompanying her was Liu Yan.

Lin Ye looked up: "You're sitting in the same row as him?"

Liu Yan glanced at Gao Yuan: "It seems like they're in the same row, with two people between them. I don't know him, but I remember his dad coughing quite badly."

Du Zhiqiang handed over his registration slip and said, "I was in that row too, near the door. To be honest, I can't remember who was sitting where. They were all coughing or waiting for X-rays. As soon as a chair was empty, someone would sit down."

Lin Ye glanced at the names he had just written down in the register.

Gao Yuan had a fever, and Gao Limin, Feng Yuzhen, and Du Zhiqiang all had coughs. No one could say for sure how many groups of people had sat in that row of chairs.

Two lines of light blue text appeared at the edge of my field of vision.

[Risk areas: Increased risk of clustered respiratory infections/nosocomial exposure]

[Key gaps: People waiting for treatment at the same time, areas they stayed in together, lists of accompanying persons, whereabouts of those who have left, and the starting point of symptoms]

Lin Ye started a new line in the registration book and wrote "Stayed in the same row as the CT waiting area, waiting for verification".

"Did your dad speak to anyone outside the CT scan room just now? Was there anyone nearby that you remember?"

Gao Yuan was still looking at the regular clinic area when he heard the question and turned his attention away: "There was an aunt wearing a blue sun protection shirt and carrying a small bag. She asked us how long it would take for the emergency room X-ray to come out. She said her husband also had a fever, was in a wheelchair, and was coughing even worse than my dad."

Liu Yan immediately looked up: "I remember her. Her husband's wheelchair footrest got stuck, and I helped her move it."

Du Zhiqiang also remembered: "The wheelchair belonged to the hospital, right? She later pushed it towards the elevator, and I thought she was going to get a report."

Nurse Zhu looked at the group of people: "Didn't she go back to the emergency room waiting area?"

The group looked at each other, but no one could answer.

The nurse next to him had already walked to the outside of the general clinic area, first letting Gao Limin change into a new mask, and then pointed to the temporary empty space against the wall at the triage desk.

The elderly man was coughing badly and was holding a receipt. When he heard someone call his name, he tried to walk toward his son, but the nurse stopped him.

"Uncle, don't push over there, come this way with me. Put your mask on and sit here first."

The old man was hard of hearing and didn't hear clearly. He frowned and asked, "What? The scans are out?"

Gao Yuan stood up anxiously: "Dad, go with the nurse, the doctor will ask you a few questions."

After the nurse settled the man into a temporary empty seat, Lin Ye slowed his speech: "Uncle, what time did you start having a fever today? Did you take any fever reducers at home? Did the lady in the blue sun-protective clothing speak to you earlier?"

The elderly woman hesitated for a moment before answering, "I started coughing this morning, and then developed a fever in the afternoon. I took a fever reducer, but I can't remember the name. The person asked when the scans would be ready, and I said I didn't know either. Her husband was in a wheelchair, coughing quite badly, and he could barely speak."

Nurse Zhu didn't delay any longer and picked up the landline to dial the emergency number of the infection control department.

After the call was connected, Nurse Zhu first reported to the emergency triage desk, and then told them about the situation in the chest CT waiting area around 7: several people with fever and cough had been taken in, and there was also a patient in a hospital wheelchair who had not yet returned to the emergency room.

Qin Hai was walking from the direction of the red zone when he heard the last sentence.

He had just finished handling the transfer, and before he had even fully lowered the cuffs of his white coat, he glanced at the chair on the outside, then at the registration book in front of Lin Ye.

"Where does the known information come from?"

Lin Ye handed over the registration book: "Gao Yuan said that his father, Gao Limin, first developed a fever and cough. He accompanied the patient for the examination and then felt chills with a temperature of 38.7 degrees Celsius. Liu Yan accompanied her mother, Feng Yuzhen, while waiting for her appointment. Du Zhiqiang was also waiting for a chest CT scan at the same time. All three mentioned that the person accompanying the patient in the blue sun protection clothing pushed a patient with a fever and cough in a hospital wheelchair away, but the name and whereabouts are currently unknown."

Qin Hai turned to Nurse Zhu: "What do you mean by hospital-acquired infection control?"

Nurse Zhu covered the stethoscope: "Keep these people on the outside first, don't let them mix into the regular waiting area. The fever clinic staff should also take them. We'll wait for their reply regarding where to conduct the initial screening. The infection control department needs to check the CT scan list first, especially the one in the wheelchair."

Qin Hai nodded: "Do as instructed. Lin Ye, call the CT room and check the waiting list for the emergency chest CT scans from 7:40 to 8:20. Ask for the patient's name, the number of accompanying persons, and wheelchair usage records, but not the diagnosis."

Gao Yuan heard the words "hospital infection" and "fever clinic".

"Doctor, my dad's lungs have always been weak. What should we do about his X-rays? Has no one been able to examine them?"

Lin Ye glanced at the old man.

The old man was coughing and tried to press the edge of his mask back onto his nose.

"The images can be retrieved, and the doctor will look at them," Lin Ye said. "Your dad is already here, so don't go back and forth yet."

Lin Ye picked up the landline. After the call connected, the voice of the radiology staff came from the CT room: "Emergency? What's wrong?"

"This is Lin Ye from the emergency department. Could you please check the waiting list for the chest CT scans between 7:40 and 8:20? Several people with fever and cough waited for their scans during the same time period, and we need to update their contact information. Also, was there a family member wearing a blue sun protection vest pushing a patient in a hospital wheelchair who was getting a chest CT scan just now?"

There was a series of keyboard clicks coming from the receiver.

"I remember the blue sun-protective clothing."

"After her husband finished the X-ray, he said he wanted to go to the emergency room to see the doctor and check the results, so we told him to go back to the emergency room and wait. The wheelchair was temporarily borrowed from the CT room and was never returned."

"Do you have the wheelchair's serial number? Can you find the patient's name?"

"I'll have my colleague check the patient number. The patient can be found: Shao Dequan, 69 years old, male, chest CT scan, examination completed at 8:07. The accompanying person's name wasn't written down; only a family member was registered as accompanying him."

Lin Ye wrote down the time and then asked, "What's the current status of the film?"

"The images have been uploaded, but the official report hasn't been signed yet. The emergency workstation can access the images first."

Qin Hai reached out and took the receiver: "This is Qin Hai from the emergency department. Send the list to the emergency workstation first, and also help us find the wheelchair number. If this patient is still in your area, don't let him leave on his own. If he's not, we'll contact the triage and security to find him."

After hanging up the phone, he turned to Nurse Zhu and said, "Notify the triage and security staff to find the family member in the blue sun-protective clothing and Shao Dequan. Once they're found, don't bring them back to the general lobby; take them to the outer triage point first. Report this to the infection control department again; there's one more wheelchair patient who's been out of sight."

Nurse Zhu immediately made a phone call, and another nurse made room for the empty seat in front of the row of chairs on the outside, and put a temporary mark on the ground with yellow tape so that the people in line behind could avoid it.

Liu Yan helped her mother sit up and asked softly, "Nurse, do we also need to go to the fever clinic? My mom hasn't finished her appointment yet."

Nurse Zhu held the phone between her shoulder and ear, and replied briefly, "Don't rush off on your own. Wait for the infection control and fever clinics to give us a heads-up about who's going where and how to get there. Someone will guide them."

Lin Ye added the last line to the register.

Initially, it was just a person accompanying someone who had a fever. Now, it has become a series of times and locations: 7:40 to 8:20, in the emergency chest CT waiting area; Gao Yuan's temperature was 38.7 degrees Celsius; Gao Limin had a fever and cough; Feng Yuzhen and Du Zhiqiang were waiting in the same row and also had coughs; Shao Dequan was pushed out of sight in a hospital wheelchair by a family member wearing a blue sun protection clothing; Shao Dequan's name has been verified by the CT room, but the name of the person accompanying him has not been registered; the infection control department, fever clinic, triage, and security have been contacted.

Qin Hai closed the register after reading it.

"If the person and the route don't match, the rest is all empty talk. Don't just write 'fever pending investigation' and call it a day."

No sooner had I finished speaking than the reception desk called back.

Nurse Zhu answered the call, listened for less than ten seconds, and then looked at Qin Hai.

"Director Qin, we found the blue sun-protective clothing, but she's not in the emergency room lobby." She covered the receiver. "The triage said she pushed her wheelchair to the elevator entrance of the inpatient department, saying she wanted to go upstairs to ask her son for the report."