Maybe you implied it, but adding to the 'going up' case, there is bullet ricochet -- also reffered to as skipping or bouncing bullets -- that makes it so that bullets will ricochet out at a shallow angle and ride out the wall or floor, making your head hittable without even aiming at it.
Here is a instructional FBI video talking about it.[0] And a more modern take.[1]
Maybe you implied it, but adding to the 'going up' case, there is bullet ricochet -- also reffered to as skipping or bouncing bullets -- that makes it so that bullets will ricochet out at a shallow angle and ride out the wall or floor, making your head hittable without even aiming at it. Here is a instructional FBI video talking about it.[0] And a more modern take.[1]
[0] https://youtu.be/7tUW0cUkNv0?feature=shared&t=240 (I think the date is wrong, other places mark it as being from 1974-5)
[1] https://www.youtube.com/watch?v=gT219NKPJh0