That finisher looks so sick, but i need to be honest, you get 5 seconds to do the whole thing, its kinda bad.
It seems that it will be only working if you finish someone really close to the body, so you enter the circle and inspect the gun.
Because if you finish from a far you really need to run to see inside of the finish
It's an easter egg, so we don't expect it to happen often. We still think the Finisher and music is pretty cool without it.