"If you think you can handle her," he agrees, and then he nods in her direction. "She could use to get out, even if she doesn't quite think so herself, even."

The solid black gelding is still in his stall, watching them both curiously awaiting his turn to be turned out, as is Nova, but Doc'll wait until Katherine leads the mare out before even moving from where he's leaned against the wall.

Watching, just in case. It's not that he doesn't trust her, and not that he doesn't trust Corella to behave, it's just...precaution.