Loud “Pop” after priming oil pump

I'm thinking this is a likely scenario... I remembered I had my exhaust ports pretty tightly taped with painters masking tape, so I went and checked to see if one was blown out. Sure enough... cyl #3 had tape that appeared to have been blown out from the inside. All other exhaust ports remained tightly taped. Also, as I was rotating the engine, I could hear the flexing/wrinkle sounds of the tape, so I knew air could slowly leak through as I was rotating.

If i was rotating through the exhaust stroke, and I had a lifter that wasn't fully pumped yet, thereby keeping that valve from opening, and air from escaping... then finally pumping up and opening that valve.... that would totally cause that popping balloon sound, as well as blowing out the tape.

Seems pretty likely to me. I think I'm still going to try a leak down test to see if there are any valve train issues. I'm assuming I'll have a certain % of leakage past the rings, since they are unseated, but I would think a valve issue would be exposed if there was one.