There are also some "ohcrap" buttons we can use in case the tank dips a bit too low or even as part of our "rotation". WHM can use Tetragrammaton as an insta-cast, mp-free, cure II (or, if you let the tank dip TOO low, Benediction); AST has Essential Dignity and a SCH can let the fairy heal and then throw a Lustrate. It's mostly a thing of practice and knowing your toolkit. A WHM that trusts their tank to keep aggro can even Divine Seal+Medica II+Regen on the tank and DPS while the HoTs tick away and, in general, if the healer is DPSing (while keeping everyone alive, of course), the run goes faster.