At some point he couldn't focus anymore on his project. He wasn't as ADD as Greed, he liked to finish things. With Temperance's breath turning cold, those gasps of air as Sloth had predicted nothing short of horrific---it finalized his installation. He found himself then moving the camera lens towards a new pet.
Something about Sloth in that dress was disturbing in an entirely different way. Usually he lured in his prey, but here she was very subtly luring him.