McCain says "horsesh*t" on live TV (or not?)

Crank up the volume and listen. McCain clearly mutters "Horse..." something. I'm not sure if he completed the thought, but I think he really did start to verbalize an internal thought and then caught himself. And then look at his eyes afterwords as he checks the see if anyone heard him.

Maybe this is what those undecideds saw that I and others missed? The body language from McCain seems to be saying, "I'm John McCain dammit! I shouldn't have to stand here and take this horseshit from this youngster!"

Update: Okay. On further viewing it could be reasonably argued that McCain was mumbling something like "of course not".