There is the rise of one articulate eyebrow at the pause succeeding 'watch', but it smooths back out again along with further explanation.

Charles' study flicks downwards, considering the ground between them. It's one of those moments where he feels like he shouldn't, and knows he will anyway. The jury is out on whether it's actually one of his better qualities. But if he's learned anything in the last decade, it's that inaction is equally a choice one consciously makes, with its own set of consequences.

This isn't exactly the same, but-- "I'll help you. If I can."