Warning for Priests in a Hospital

If patient (who is a Cohen) is in a room in a hospital for medical treatment, and sees that there is an alert for Cohanim, what is better, to close the door or to leave immediately?

Since when he leaves, he passes through a place that is open to impurity, and when he closes the door, there is an opinion that the impurity does not pass, he should close the door and wait until the alert for Cohanim is over.

The author of the Aruch HaShulchan wrote (section Yoreh Deah, chapter 371): 'Important later authorities [Drisha and Shach in subparagraph 15] wrote: Even when an impurity comes into a house, if the Cohanim intend to close the doors and windows of their houses and not to leave them until after the removal of the corpse, they do not need to leave their houses. As long as the room has not been opened, the impurity does not enter it. On the contrary, it is forbidden for them to leave by opening the door next to the room where the corpse is, because when they open it, the impurity immediately enters, unless they can leave through another door that is not next to the room where the corpse is. Then they are not obligated to leave, but they can leave if they want, just not through the door where they will take out the corpse, for the reason that ‘in the end the impurity will leave’, as will be explained.'