Just remembered one situation that happened to me. Was in the pool doing a training scuba dive. My equipment had been out on the patio for a while. I had a inflatable tube used for emergency signaling. Anyway I took that and proceeded to blow air into it through a valve. Just then a cockroach crawled out of the mouthpiece and into my mouth.
I cussed a little and choked on water I ingested. I sure didn't scream like this guy.
I read the book "Descent into Darkness". The author was a Navy salvage diver during WWII, and dove on the wrecks at Pearl Harbor. You needed nerves of steel to do this work. Yet he was deathly afraid of spiders. On one dive, he had to use a spare suit and helmet, while his was being repaired. After being lowered to the worksite, a spider suddenly appeared inside his helmet, and started crawling around. He was powerless to do anything about it. He panicked, and it nearly cost him his life.