Sam's mind is broken, but his instinct to save people is strong enough that it still gets through the mess. He still fights as hard as he can. And, I think this scene just brings to light the reasons I love Sam Winchester.
Supernatural Destroyed My Life: Season 1 I got hooked. Seasons onward is going to break me entirely and destroy any semblance of normality I have to my life. Thanks Supernatural. This is all your fault.