The US Army, at least as far back as 1988, would modify training based on a heat index. Still, you would see heat exhaustion occasionally - soldiers getting dizzy, losing coordination, even getting listless. Include headache and nausea as common symptoms. Even in the days before red card and coddling, the ARMY took heat conditions very seriously.
In my opinion, this was the case yesterday with many of the players right on the edge - motor skills, strength, cognitive, all being challenged. Allen's throw into the turf on the missed TD likely doesn't happen unless he's totally gassed. Maybe Davis make the football move and maybe Milano has better focus and intercepts the ball. Who knows............ I'm rather surprised that the heat management solutions aren't better - even for the visiting team.