Knight with Wand

The red line is the route of Doson's escape, and the blue line is the escape route of the protagonist. The intersection is the location of Selva Village. It is just a rough drawing, not necessarily accurate, just to give you a general impression of where Selva is.

So although Selva is a remote mountain village, it is isolated from the border by the Nightmare Forest. The south is very safe and is not considered a border. It is just a mountain ravine, if Doson does not accidentally come in.

So the baron did not seal the three protagonists at the border, but instead sealed them in a corner far away from the border. He was also afraid that the talents would die before they grew up because of war or something else.