Ouch! Tough break, no pun intended. Initially, I find it hard to believe that a simple 4 feet drop would cause that amount of damage to a phone while encased in an OBD. However, I have no reason to doubt the incident, as others have.
It's simply one of those things. Bad timing, wrong place at the right time. My iP5 is currently housed in an OBD. I don't doubt that my iP5 may receive damage during an accidental drop. All I can do is attempt to limit the damage and whatever will happen, will happen.