A really good head coach would have....

A) Kicked it short to the Chiefs

B) worried less about protecting the sidelines and  going prevent and more about putting pressure on the receivers and Mahomes

The squib or equivalent  kick takes maybe 4 seconds off the clock, maybe more. That changes everything. And the only thing a prevent defense does is prevent you from winning. A coach like John Madden would have gone for the jugular. Coaches from the  Parcells tree would have done the same thing. Play your deep thirds if you want but have the corners and LBs chip the receivers, especially Kelce and Tyreek, off the line. And send 5 at Mahomes. Make him throw it under duress at a guy who has a defender chucking him 5 yards off the line. That's when Mahomes makes mistakes. When his receivers are thrown off their routes and he has to make a quick decision.

I don't care who your opponent is. You can't lose a game leading by 3 with 13 seconds left and kicking off.