On many critical plays for the chiefs, the dolphins went all-out blitz. They brought 7 or 8 on most ocassions.
That is selling out. If it works, great. You get the big sack and control that series and possibly the game. And it sure looks amazing when everyone is around the qb. They appear to be swarming to the ball.
But they were lucky. If it hadn't worked, Miami would have been in a heap of trouble. The scoring would have been easy for the chiefs.
I'm not a fan of selling out to the blitz, but sometimes it works....