This is the most absurd question ever

But SciFi is showing Nemesis and I've always wondered. And this is probably one of those things that you're not supposed to think too hard about.

Anyway, when manually dialing the gate, how does it know when to "lock"? How does it know Teal'c's just not pausing to get a better grip? And how does it lock? If the gate doesn't move for so many seconds does it assume a lock? I know, I know. I'm totally over thinking things. But I have to know!!

PS - COLIN!!!!!!!!!!!
PPS - Whenever I see this ep I always think of Anais' Scratch. So, in my head as soon as the episode is over, Davis and Daniel end up in the bathroom making out. :-D