Torn ACL?

If RG3 tore his ACL, he is an idiot for playing.  I didn't see the game past the first quarter, but he looked done when he tweaked his knee.  He could have partially torn it on one play and fully torn in later - I did the exact same thing a couple years ago.

I don't see how a doctor does look at this on the sideline.  Anyone trained can tell an ACL injury just by physically tugging the knee.  I suppose you can't quite tell if the ACL is partially torn.