Замедленное видео пролёта пули через блок геля.

The flash/explosion in the gel hasn't been very well explained so far. The best explanation I have is that the hot bullet vaporizes some of the gel (which is flammable) and between the friction, heat of the bullet, and air being sucked into the temporary stretch cavity, as the TSX collapses it acts like a diesel engine and compresses the mixture of heated gel vapor and air until it explodes. You can see the exhaust gas exiting the entrance hole