Their retreat seems to put fresh heart into the building's defenders. It's slow going, down the stairs; it would be slower if there were any way for the defenders to press them from two sides at once.

One Slayer is moving with a crossbow bolt through her arm, protruding front and back. At least two are being carried or supported by others. Nobody's getting left behind.

They're nearing the bottom of the stairs, and two Slayers peel off from the rear to make sure they're not backing into more enemies.