I think saying 1% is a pretty big exaggeration. They only seem to have 100M-ish HP for the DPS challenge, unless they white hit super hard (Basically making a really short enrage), I'd saying anyone like 880+ could probably pull it off with the right survival set-up/after learning the mechanics of the challenge. Although, as I mentioned, this is just based off of third hand info/screenshots until I get home.