Suppose you where lion hunting with your buddie, he sees a lion first and he hits the MGM type lion hard in the chest with his 375. The lion immediately attacks him, jumps, and you shoot the lion in the center mass like a quail in the air with your 500 NE and your buddie flat misses his followup shot. The lion misses his leap and goes down mortally wounded, runs off and is found dead shortly thereafter.

If my buddy shot the lion that was attacking me, after I failed to stop him, I would give him the trophy and volunteer to pay to have it mounted.