I don't think it was a dead ball. It looked like they blew the whistle because of the cheerleader. From what I can gather Pitt was not trying to take a timeout. Btw, I e-mailed a friend of mine who officiates high school and college ball and he sent me this:

Rule 10, Section 2, Article 9.... Team followers, as in Rule 4-27, shall not commit an unsportsmanlike act, including, but not limited to, the following: Delaying the game by preventing the ball from being promptly made live or by preventing continuous play, such as but not limited to,followers entering the playing court before the player activity has
been terminated.