Safety question: Uni-spotter on quarter with gas tank in?

Ive been doing body work for 20+ years and have never had any issues with a uni-spotter but once started a Duster on fire while welding a 1/4 panel!! I had the trunk closed with no lock in the trunk and no screw driver ready, got pretty panicy, so my word of advise would be to have a plan if something would go wrong but I don't think I would go as far a pulling the tank unless there were something like a leak.