It's clockwork, really. Hawke stabs and steps aside for a well placed cold spell from Merrill to land, and she sidesteps again to make room for Isabela.

The only drawback, really, happens when one of the younglings manage to get past Varrics support fire and wrap it's jaws around Hawke's forearm. Hawke grimaces, and ends up having to stab the beast a lot to dislodge it.