Fox
He didn't tell anyone on his team what was going on.
Stafford was wearing a microphone during the game, and the Lions released this fantastic video of what he was yelling during the final drive. Just listen to to the 1:01 mark when he's FREAKING OUT, yelling, "Clock! clock! clock!" at his teammates before diving in for a TD.
It's a high-pitched squeal.
Amazing (gets good at the one-minute mark):