You're digging a hole here mate. Plenty thought at the time Mullen had "bottled it" but it's more than clear now he's suffered a fairly serious injury. I'm unconvinced he's a decent keeper but that's a different matter. 

In fact in the same game the Celtic keeper came close to getting caught in possession 3 or 4 times, shit happens, we move on, if it didn't it wouldn't be St.Mirren.

why would that be ?  he got caught in possession, happens to loads of keepers ?