I think it is best if we make it blatant:
1) your character is in the church, you can craft how they ended up there.
2) if you are not with the party the likelihood of your survival becomes difficult, as the GM has stated. This is a group survival roleplay.
Honestly I should of stated this when we have our first "different" POV.
Your characters backstory is important, but right now lets look forward and not backward.
Double Edit: I suggest people don't worry about their backstories, just focus at what's at hand. We're introducing ourselves then going to search the church for stuff.
DING DING DING we have a winner! Exactly this.