One of my biggest fears is what happened to you as far as the gun not coming out. I have a P229 that I carry in a Galco summer comfort IWB and I haven't had any issues yet.
I did buy a Uncle Mikes, Fobus knock off, with tension screws. I adjusted the tension screws to the point where the gun won't fall out when you flip it over, but when I put it on my belt I can't get the gun to budge.
If I take it off the belt and pull on it the gun comes right out! Still trying to figure out what I'm doing wrong! Needless to say I haven't worn it yet.Let's just pray your nightmare never comes true!
RR