Now that I think about it, it wasn't that big of a horde and there weren't even any Overlords in it. That's the worst part about it. And you'd think I would have died shortly afterwards, but no, I survived without a problem. I don't think I even had to heal myself.
I've had Fawkes get killed against an army of Enclave soldiers too. But that at least made sense, since there were probably over a hundred of them. Not to mention I died at least five times in that same area.