The clock restart after a penalty rule is interesting:
McVay probably made the correct call, as giving New England a 1st-and-20 still allows them to milk another 40 seconds off the clock, which means that the Rams would have had 30 seconds to drive the length of the field with no timeouts even if the Pats fail to score.
I have thoughts about that rule. One day, a smart coach is going to have his team prepared in the perfect spot to take advantage of it to win a game they should lose.
There are different scenarios, but here's the one I'm thinking of. Team is on defense losing by a point. 2:40 left and the offense has a third down and say they are backed up in their own end. Runner breaks through the line and has the first down in bounds. This should be game over. The clock runs to the two minute warning and then it's just three snaps in victory formation for the win.
The defense should be coached in this situation to commit a penalty. Once the runner has the first down tackle him by the facemask.
It's first down either way. Now, you give up 15 yards but the clock stops and you essentially have traded that 15 yards for a time out that keeps you in the game. So, they run on first down and it goes to the two minute warning. Now you have a chance to get the ball back with 30 seconds or so left. Outside 5 minutes left, the clock would be wound after the facemask, but inside the last 5 minutes, you have a time out. Down by a field goal this at least gives you a chance to block a punt or maybe throw a sideline pass to get in FG range. There are other variations.