"Fuck!"

Anders immediately resorts to the lightning, because they're outnumbered and in trouble, and he won't stand a chance with just a dagger.

And Anders isn't the only one moving to attack with magic. Nellie panics slightly, moving to put up a barrier to block as many of the hoard as possible, before she attacks a few of them with an unexpected Entropic spell, stunning a few of the Darkspawn.