"There's mirrors in there," Strange clarifies. This is apparently enough to be a point of contention despite the fact that mirrors are glass. "And it'll take more of an impact than banging my elbow. My mirrors have shattered when I was shot by an arrow, bit by a wolf, and punched in the nose."

And probably will end up breaking at some other point in the near future because that's what happens when you're a glass cannon.

"I can remove the broken pieces by turning into smoke. However, that won't stop any, erm, piercing of certain organs when they break in the first place."

Knock him hard enough and it's internal bleeding city.