Loghain has a shadow, though he may not realize it. He probably assumes so on some level just being who he is, but Teren is pro at being shady, and it's been a while since she got to stretch these muscles.
It's easy enough to be near enough to hear and see him when they're both doing Warden things, and though she always keeps one ear open, Teren's real priority is anytime Loghain is interacting with the others, Alistair in particular.

One can hear a lot while sewing. Or brushing Boots. Or just, you know, existing in someone's general vicinity. Subtly.