The demon is most definitely slowing down, and while he thinks they could shatter it without much more from him, he's also fairly certain they have it contained.

"A rock fist might shatter it!" But even as he shouts back, he's turning to the nearest of the injured wardens, glad that Merrill's slip made it sound like she was just saying another word. The deception might not be that well done but he wants that flimsy shield anyway.

Anders kneels next to the first Warden and casts, seeing if he can help save the guy.