doom/sergis, the first photo is unspecific, what do you mean by "here"?
on the left wall, on the furthest?
close it off and put a roof over it?
as for the 2nd, i tried to change that in a2
3rd, i just changed it a little
and 4th, that's to show it's a one-way door
all classes can see the no entry texture from one side.