I would think the odds of such catastrophic failure to be almost zero. But, if it did, I would either just stick it inside the waist band and carry on my business, or carry it out to the vehicle while holding it with an overhand grip on the receiver (not the handgrip).
This ^^. And the OP's description is the holster failed at the point of attachment to the belt/pants, not that the handgun came clattering out of the holster. Which means I would have picked it up still in the holster.
In the interest of full disclosure, I have had a paddle holster that was put on improperly (over the belt and inside the pants as opposed to over the belt outside the pants) tumble loose when I was bending over to pick something up. The holster functioned as it should have 0 the handgun remained inside the holster which also protected it from scratches. I said "Oops", picked it up, and stuffed it back in my belt the way it should have been in the first place. Then I got ribbed the whole rest of the day for my holster jumping out of my pants.
But I'm still trying to figure out how you would have a catastrophic failure of a plastic holster (which could be anything from a Fobus to a SERPA to you name it) that would not involve you touching the holster at the time of the failure. The only thing I can come up with is somebody behaving like the cops who seem to believe that their holstered handgun is really an elbow rest.
stay safe.
