I think Braum fakes his death.

He's way to manly and strong for anyone on the rift to kill him but he wants to be fair so he takes a seat on the bench when he believes the enemy deserves it. I mean look at it, it's like watching WWE he melodramatically reaches for the shield and he pulls it over his face so you don't see that he's giggling underneath. Then as the shield lands on him he kicks his legs up to make the impact look hard but it's all a ruse. Also it may look like when the shield hits him on the head, it hurts hella lot but it's all part of the show, look at his massive chest muscles. The muscles absorb all of the impact before the shield touches his head.

If there's anymore doubts I'd just like to point out this skin.

http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Braum_2.jpg