Falling out of the bunk bed and damaging the floor.

If the depression is four inches, it. is likely all the way through. Very few of these foam core floors aremore than two inches, most are one inch thick,

Mine is slighty over an inch of foam, but bottom layer is galvanized steel, supported by 1 inch square tubing, so the result of a fall like that would be a shallow dent and more head damage. The floor giving way probably helped reduce severity of injuries.