I think the real danger associated with helicopters is not related to engine failures, I have been a lot around helicopters (in the military and in the civilian world) and I never heard of an engine failure. Most of the occurrences were related to collisions with things on the ground.
Sir, if you were aroound helicopter pilots that much, you'd know we are perfect. WE do not hit wires, roll over while trying to puck up to a hover, or other such pedestrian things. If we crash, it'll be in a most spactacular way and because our machine failed us.
Seriously, though, you are right that you can have your ass handed to you in about a half second in a helicopter. Usually, those are mechanical failures, such as loss of t/r components, mast separation. We try to and train to mitigate the human factor much as possible. Your reference to "collisions with things on the ground" is very true. I know pilots who have done it. Wires, trees, heck I know a guy who got charged by a bull (no contact). I also know folks who've gone swimming in the GOM after their engine puked. The difference is that with those frirst examples, WE, the pilots, have more control. A better high/low recon, a more controlled approach, not landing near livestock -- those are thing we can do to mitigate the risks. The mechanical stuff, we do our best with the preflight.
In short, your assessment of the dangers associated with helicopters wild be more accurate if it placed the threat not on the helicopters, but on some of the people flying the helicopters.
BUT, as I've already pointed out. We're perfect. There is no danger.

Q.E.D.