Questor: Ouch! Dang good reason to have that 1911 checked out. But, to be honest I would think that you would see some indication of near catastrophic failures before they happen. I mean, even if the steel is old and the piece has seen considerable use, there should be a crack somewhere that would have indicated a problem pistol. I can understand the chamber area of a 1911 coming apart and creating some shrapnel but to have the slide fail so drastically tells me something was radically wrong with that piece before it came apart and someone should have noticed.
I have seen cracked frames that just kept on tickin' - in fact, in two 1911s in particular, they even shot more accurately than before the frame cracked - must have tightened up the slide to frame tolerances a bit but even then, nothing came apart. When one finally stopped working it just stopped, period. There was too much pressure on the slide from the cracked frame (lengthwise crack from the magazine well to the sear plunger hole) and that seized up the slide. Mikey.