The other well unknown rule is that you need 3 seconds to get a spike off with a running clock. If it is considered to be less than 3 seconds, it will be considered out of time. The ref was fighting through the line with 4 on the clock.Who's targeting you?
The ref has to get up there. He was probably as surprised as anyone to see that play call. It was a very risky call and the time it takes for the ref to spot the ball should have been taken into account before they made the play call. It's not instantaneous.