In what episode of Full Metal Panic! does sousuke get seriously injured?

Answer 1

Well, he gets injured numerous times. Do you mean at the very beginning when he attempts to rescue Chidori during the hijacking incident or near the end when he fights Gauron on the De Dannan. (Though for the latter, I can't remember if/when/where he was actually injured.) If you could be a little more specific that would help.