door frame removal
if its an interior door and you have a sawzall, air compressor and trim nailer or access to them, removing and installing the door frame is actually quite easy.
Once removed you should have 24 - 24 1/2 inches.
Remove the door and hinge hardware.
Take a flat bar and remove the trim (both sides), use a pair of pliers to pull the nails out the back side of the trim so you don't damage the fronts.
Take the sawzall with a long blade, I use a 12tpi and run it between the door jamb and the framing structure, both sides and top.
Now the whole frame should come out pretty easy.
Either cut off any nails that may still be protruding from the door casing or pull through so as not do damage exposed sides of door jamb. hammer any exposed nails into door framing.
Install safe.
reinstall door jamb, use level and shims to plumb. liberally use trim nailer to secure door jamb, re-install trim, door hardware and door.
Then sit back and savor the fact of what you accomplished.
BTW, You can always remove the trim on the back first so you can measure the opening to make sure there is enough room.
Hope this helps,
Al