He reaches up, gently brushing Nate's hair back, listening and making sure he's hearing everything that's being said. Teren's sinking a little in his opinion with this - she'd clearly laid a trap for Nate and Anders doesn't approve of that.

"The spider invited you into her parlor on terms she set, waited for you to come in, and was prepared. Alistair has a good rapport with her. If she tries to do something again, give it to Alistair. It's not easy to not engage. I know it's not. Especially when someone who knows better isn't showing it. But don't engage, please."

Maybe engage is the word that will be more clear than fighting. Anders isn't too attached to the wording, just the man he's speaking with.