Why does Voldemort choke/slap Harry right before their final duel in Deathly Hallows Part 2?

We all know Voldemort hated all things Muggle and believed magic was superior, so why, in Deathly Hallows Part 2, does he choke, slap and hit Harry manually right before their final duel? Wouldn’t it make more sense for him to use a magical method, or even just straight up use the Killing Curse? Is there ever an explanation given for this?