Oh, I get shot at, set on fire, and blown up plenty. My armor's different, though. I've got a healing unit-- it's like having a built in cradle. If I'm wearing my armor and someone shoots me, and it manages to go through one of the soft parts, the healing unit actually just.. heals the wound. From the inside out. And I'm good as new within a few minutes. Too expensive to use on the average Spartan, but they make sure I can take a licking and keep on ticking.
Your Medi-Gel is pretty awesome, though. Wish I'd had that during the war. I think it'd be helpful in the suits, rather than requiring a human hand to apply it. Sometimes you're own your own and you just can't.