Can an arrow bounce out of a deer?? Absolutely. A couple years ago a straight up buddy with years of experience called and said he had hit a deer perfect only to see the arrow barely sticking out the entry side as the deer took off. It happened so fast he was sure he had only got a few inches of penetration. He watched the arrow fall out the entry side after a few bounces as the deer took off. He quitely got out of the tree stand and did not trail it. We decided to wait a good while before trailing. Went back and the deer had only barely made it out of site and piled up! Upon examining you could see the arrow had made it through the vitals, both lungs a perfect hit, slammed the other off side shoulder without exit and bounced or blew back out. I've since heard very similar experiences with the same result. My guess is it did exactly what you said BLEW back out the same entry hole from lung collasping etc. After all it is a pressurized compartment, who hasn't heard the air get knocked out of themselves or someone else. The only difference is your glue failed and your broadhead stuck in the off side or pulled out as it came back through. I would think its alot harder to push a broadhead down through the shaft as opposed to pulling it out. Pulling it out tests the glue. Just my opinion.