We marched through the forest while I constantly had an eye on the coin in my mind.
The reason I had decided to first go back to strengthen myself before looking into the future was because I figured we still had some time.
Henry's father had told me about the shadow possessions while we had crossed the cave on our way to the open space.
From possession to suicide, it took two weeks.
So even if Henry was special or the worst case and lived faster through the symptoms or whatever, we surely had a day before he would try to commit suicide.
Moreover, Mr. Devin had again confirmed what I had already seen in my vision, and that was that one shadow entered their victims, but two emerged. So it was their form of breeding or whatever.