The fumble wasn't reviewed. The SEC official didn't buzz the field, Pruitt didn't question the call and nothing was done. UT's players were sure it was a fumble and the announcers agreed. In a situation like that, the HC has to call a TO and question the on-field ruling. You'd better believe Muschamp wouldn't have been passive about it.
I believe whistling the play dead means the fumble can't be advanced. Bituli's TD wouldn't have counted, even though he ran it back, but the fumble could have been reviewed and UT given possession. SCAR wouldn't have scored and the momentum would have shifted in UT's favor.
SIAP, Jesse Simonton tweeted that Tuttle and Kirkland both said Pruitt knew it was a fumble, but couldn't get the officials to review it because it was blown dead...
And just because we didn't see Pruitt's face turn purple doesn't mean he was passive. In fact, he doesn't exactly come across as a passive coach to me.