while we might be biased due to RPG's and MMORPG's where doing 17% (or 1/6th), crit or not, is massive, in the current situation we already see Lance Knight Lady on the floor with no Healer present. if they had 2 knights provoking the boss in turns, this might be pretty achievable, but with one hurt/down already, it's an increase in challenge. and we still don't even know whether the Ice Lady can even do good damage by herself without the protection of her knight.
but since i doubt they'd kill of a noble, they'll likely win with everybody intact.