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

After the laboratory confirmed the sample retention requirements, the internal line was immediately disconnected.

Xu Mingzhe laid the three epidemiological registration forms that he had just put aside back on the worktable.

After checking the sampling numbers, Li Qian, the staff member on duty in the infection control department, separated the three households' information: "Asked them separately, one by one. The patient's own statements and the family's supplementary information are all clearly marked."

Xu Mingzhe looked at Lin Ye: "You take over Gao Limin's case first. Don't start by asking about his fever today; go back two weeks and focus on the time he was away from home and the places he stayed."

Lin Ye picked up the intercom and connected to Gao Limin's clinic.

The nurse across the room placed the phone by the bedside. The old man coughed a few times, but his voice was still relatively clear.

"Uncle Gao, your son filled in that he's been home these past few days. Thinking back two weeks, did he go to the market, restaurants, or hospital? Did he attend any gatherings or lectures?"

"You go to the market every day, does that count?" Gao Limin replied at first, then changed his mind, "I went out last Sunday. Someone was handing out flyers at the entrance of the community, saying they could give away free lung function tests and a bag of laundry detergent. I went there around nine o'clock and didn't get back until almost noon."

"Do you remember the location?"

"Kangning Hotel, second floor. First, you have your blood pressure checked when you go in, then you line up to have your blood pressure blown through that tube. Behind you, someone was talking about what you should eat if you have lung problems. I listened for a while, didn't buy anything, just got some laundry detergent and left."

Lin Ye added the day of the week, arrival time, and hotel name to Gao Limin's form, and then asked him if he was traveling by bus and was accompanied by an old neighbor from the same community.

The elderly man couldn't remember his neighbor's full name, only that everyone called him Lao Gu and that he lived in the next unit.

After the inside line at another observation point was connected, Lin Ye told Gao Yuan about the Sunday schedule that Gao Limin had just added.

There was a few seconds of silence on the other end of the phone: "He told me he spent the whole Sunday morning playing chess downstairs. When I got home from get off work, I saw that bag of laundry detergent again. I asked him where it came from, and he said it was given to him by the community."

"Don't keep calling and asking about your father," Lin Ye reminded him. "Tell the nurse what you know about the time and which unit Old Gu lives in, and leave the rest to the infection control team."

Gao Yuan gave the building number and then muttered a complaint: "I've told him twice that he buys health supplements, and now he listens to these things when he goes out, but he never tells his family."

Li Qian and the clinic nurses were responsible for asking Shao Dequan questions.

Chen Xiulan sat in the registration area on the outside, initially insisting that her husband hadn't gone anywhere except the hospital and home lately.

Li Qian brought up the issue of last Sunday, asking her husband if he ate lunch at home and what time he left the house.

Chen Xiulan thought for a long time and suddenly remembered something: "That noon I waited until 12:30 before he came back carrying a blue bag. I asked him where he had been, and he said he ran into an old colleague and chatted for a while."

The telephone line inside the consultation room was still on. Shao Dequan heard this from the other end, coughed for a while, and then spoke: "I just attended a lecture, what's wrong with saying that? They didn't charge me an entrance fee."

"Where did you hear it?" Li Qian asked.

"Second floor of Kangning Hotel".

Chen Xiulan immediately chimed in: "Isn't the blue bag printed with 'Anhe Health'? That bag is still at home, containing two boxes of plasters and a medical examination card. He said it was a gift from an old colleague, and I immediately felt something was off."

Shao Dequan's voice suddenly rose: "The plaster was given to me on the spot; I didn't spend a penny. Don't talk nonsense in front of the doctor."

"Whether it cost money or not can be decided later," Li Qian interrupted them. "What we need to verify now is the date, the time of arrival, and how long we stayed inside."

Shao Dequan admitted that he also arrived at the scene around 9 a.m. last Sunday and left around 11:30 a.m.

He sat in the back row by the aisle, changed seats once, and even ate small breads provided by the organizers with the old colleague who brought him there.

As for the other people present, he couldn't recall a single name.

Li Qian then pressed for details about what was happening inside the venue.

Shao Dequan recalled that the back door remained closed after the event started, and the air conditioning was on full blast. Some people in the front row complained of the cold and gradually moved to the back to change seats.

People undergoing lung function screening lined up on one side of the venue, and staff changed the mouthpieces every round, yet the waiting people were very close together.

Around 10 o'clock, warm water and small bread were distributed, and the people who were originally sitting lined up again in the aisle.

Li Qian added the closing of the door, changing seats, and queuing twice to the exposure environment section, and wrote "Shao Dequan's personal statement" next to it.

She labeled the activity bag with Chen Xiulan's name.

Xu Mingzhe checked the dates and locations on the two forms and put Xu Wenliang's form on top.

On the monitor screen in the clean zone, Xu Wenliang was still wearing an oxygen mask, and his blood oxygen level remained between 93 and 94.

Luo Wenbin called back from the observation area: "He has to stop after saying three or five words now. We need to get his medical history from his family first. Once his breathing stabilizes, we'll have him verify it himself."

The call had barely ended when the emergency room called again.

The clock on the wall had already passed 11:20. Nurse Zhu was doing the night shift handover. Nurse Zhao had arrived at the nurses' station according to the night shift schedule. She had just changed into her work clothes and was checking the situation at the triage point and the second consultation room.

"I've handed this over to Nurse Zhao," Nurse Zhu said on the phone. "The outer row of chairs has been cleaned and is still empty for now. I've checked all three phone numbers—the general duty officer, the fever clinic, and the infection control center—so she knows which one to transfer to if it rings."

The phone was quickly handed to Nurse Zhao.

She first asked Qin Hai if he was going back to the emergency room. Upon learning that he was temporarily staying at the fever clinic, she immediately took over the emergency room duties: "Okay, you guys watch over there. There's a doctor on duty in the second consultation room here in the emergency room. I'll oversee the triage and internal lines. If you really need to add more people, let me know in advance. Don't wait until someone's already at the door before you tell me."

Qin Hai confirmed that the doctor on duty in the second consultation room was still there and ended the call.

On the other side of the emergency room, Nurse Zhu signed the handover sheet and left the nurses' station on time.

Xu Jing is still outside the fever clinic.

When Lin Ye walked to the glass door inside the registration area, she had just finished a call with her mother and had already asked her father about his activities over the past two weeks as required by the hospital's infection control requirements.

All his mother could say was about the vegetable market and one outing, but Xu Wenliang never mentioned where she went after he returned home.

"My mom found a card in his pants that he had taken off." Xu Jing held her phone up to the glass. "She was too scared to take it, so she took pictures of both sides."

The photo shows an event voucher with two creases, the front of which reads "Free Lung Function Screening," and below it is the multi-functional hall on the second floor of the Kangning Hotel.

The date was last Sunday, and the entry time was listed as 8:30 a.m.

The back is stamped with the red seal of "Anhe Health Consultation Service Center", and there is a handwritten number 37 in the lower right corner.

"My dad told my mom that day that he was going to see his old coworkers." Xu Jing stared at the photo. "He usually hates these kinds of lectures, I don't know why he went."

Lin Ye asked her to send the original photo to the infection control department for safekeeping, and then asked if she still had any other items from the same event at home.

Xu Jing called her mother back, and her mother took out a towel with the same name printed on it from a cloth bag behind the door. The wrapping paper also had the event date and hotel address written on it.

Since Xu Wenliang was unable to personally verify this itinerary, Lin Ye marked "Provided by family member, pending verification by patient" after registering the information, and noted the source of the photos and the family member's account separately.

Lin Ye turned the three watches to Xu Mingzhe: "Gao Limin and Shao Dequan both arrived at the second floor of the Kangning Hotel around 9 a.m. last Sunday, and both of them stayed for more than an hour. The tickets and items found at Xu Wenliang's house were for the same event, but we still need to wait for him to verify the specific arrival and departure times."

Xu Mingzhe reviewed the sources of information one by one, and then asked Li Qian to contact the duty officer: "Report according to common exposure locations. First, verify the event organizer, hotel venue records, and number of participants. For now, write 'pending verification,' don't directly write this place as the source of infection."

The on-duty officer took over external contacts and reported the preliminary information on the three cases of common exposure to the local CDC staff.

The infection control department continued to register the companions and family members of the three patients separately.

A little over ten minutes later, the night shift receptionist at the Corning Hotel called back.

Last Sunday, the multi-functional hall on the second floor was indeed rented to Anhe Health Consultation Service Center, which held one session each in the morning and afternoon.

The receptionist recalled that the organizers brought in several boxes of event bags, bottled water, and folding display stands in the morning, and then a new group of attendees arrived in the afternoon.

The venue sign-in sheet was taken away by the organizers after the event, while the hotel only kept the rental contact person.

Li Qian dialed the number using the phone next to her, but the phone was immediately switched off.

The phone at the hotel reception was still ringing. After the receptionist finished speaking, Xu Mingzhe asked again, "Approximately how many people came to the event this morning?"

The receptionist paused for a moment, as if flipping through the day's venue log: "There were fifty-six chairs. When we went in to collect the water bottles after the event, the venue was almost full."