[Rain Man]

My initial hunch was that the human could survive as long as the armor was all joined well. I don't think a tiger could bite through armor.

But tigers are really strong. My initial concern was that the tiger might get a grip on the helmet and yank it off. But the more I think about, I think the tiger would win a different way, albeit in a way that's unsatisfying to either party.

I think the tiger would flounder about for a while, but eventually it would get a good grip on an arm or leg and rip the whole thing off at once, both armor and flesh. That would kill the person, but I also think the tiger would have a hard time getting the arm out of the sleeve to eat it. It would be like eating crab legs without pliers.