Yes the concrete was poured into the decking after placing the rebar grid in place over it. Concrete is 4" thick overhead. I got the decking from Shoal Creek Building Supply. I don't know if they offer a tumbler lock, I could not find one listed on their website.Drooling... nice job.
Is the ceiling concrete poured directly into the steel (or metal) decking? Where did you get the decking?
Does snapsafe offer a tumbler lock?