Video Request: St. Johns at Seton Hall - Inadvertent Whistle

[HokiePaul]

I always had assumed that it was the officials who started the clock in college -- I usually see at least 1 officials with his/her hand on the timing pack behind their back to turn it on. I had assumed this was the official start of the clock -- and I also assumed that the whistle automatically stopped it.

Is this correct? If so, then why would the official have been worried about a late start to the clock if he was the one starting it? And if not, what is the official turning on behind their back with the timing pack?