Mahomes said he didn’t realize his helmet was broken until teammates told him, and that he wanted to stay in the game even with a compromised helmet.

“I didn’t know what happened in the moment but I got in the huddle and everyone was telling me, but I was like, ‘I got y’all, but I’m not coming out of the game, so we can figure it out on the sideline,’” Mahomes said. “It was a first for me.”

Eventually the officials stopped play so that a replacement helmet could be given to Mahomes, but Mahomes said that helmet was so cold that it was difficult to get on his head.

“They have a backup that’s out there. We have to talk about where we store the backup because it was frozen — when I tried to put it on it was completely frozen. I couldn’t put it on,” Mahomes said.

It all worked out, but this never should have happened. The companies that manufacture football helmets are required to put them through safety testing before the helmets are approved for use in the NFL, but it’s unclear whether that testing is done under the extreme temperatures that Kansas City experienced on Saturday night. Both the NFL and the NFL Players Association should insist on testing helmets in subzero temperatures — and if there’s some temperature at which it’s too cold for helmets to perform reliably, then it’s too cold to play.