Well, at least you'll have the comfort of knowing you'll probably make it if the building collapses.
Unless of course you have to actually stay in your nightmare coffin for as long as supplies last, floating in your own urine and feces.
Or you fracture all your delicious calcium and get severely concussed from falling several stories, because physics work the same way inside a metal sarcophagus as anywhere else.
Or you're trapped in a horrible upside down position because the devouring horror bed didn't conveniently land the right side up and there's no room inside to turn around.
Or you run out of oxygen, which you definitely will.
Or any of a million other horrible things that may, and definitely will, happen.
From toe to tip, this is an Idea Guy design.