Daring, risky, but used as a last resort.
Sounds like this DM's rescue to me. I didn't say it was a wise choice... just heroic.
When I used the fireman example and I said "we" I didn't mean the fireman's peers. I meant the general public. When something like that happens, It's all over the news. Hero!.. and it's true. It is heroic..maybe not wise, but heroic.
The firefighters that kept going into the Twin Towers on 9/11....I remember the media calling them heros, but I don't recall the media ever calling them stupid.
If I had been in this DM's fins, I probably would have attempted the rescue, but realistically, I probably would have chickened out and turned back before reaching him...and when I say "if I had been in his fins" I mean if I had his experience, training, and knowledge of how best to live through a situation like that. I don't really know what I would do if I were him becase I don't have that training yet. I do know that if I were me (which I am), and I was on this dive, I would NOT have gone after him, even if he were my buddy.
The DM acted heroically....but I would not want to be one of his loved ones.
I'm not disagreeing with Mike. I'm just saying there are valid arguements for both options.