JPPE, sorry to hear about the incidents and wish the racers complete recovery. At the end of time trials, racers get delirious trying to go has hard as possible at the end. And it is important to keep your head up at the end since there is a lot of obstacles and traffic at the end of races. There is a lot of emphasis on keeping ones head down and out of the wind in time trials. That is fine as long as one does not sacrifice visibility. One way to manage you head profile is to lower it for a count of 5 and then look up the road for obstacles, lower it and count to 5 again. Some pro racers who have cars that follow them and get instructions and obstacles called out via race radio (assuming radios are allowed).
I have two aero helmets. One has much better forward visibility than the other. I use the faster, lower visibility (less distance ahead) helmet for races on the track where I am the only one on the track or team events. For road TTs, I use the other aero helmet.