He does know her. He knows how she pushes herself, how hard she works. It's an indication of how worried she is, therefore, that she doesn't actually put up any argument. Instead, she lets Watson help her up, and takes his arm, trying not to lean on him too heavily.

'After all you've done for me, I think I'll let you insist,' Tayrey says quietly. She'll try her best not to be a difficult patient, at least. 'Maybe it's for the best that I'm not alone, anyway. I'm... the dizziness hasn't gone, and there's visual disturbance when I move too much. I don't think it's a serious concussion. I'm up and talking to you! But it's... something.' She's still trying to downplay it, as if optimistic thinking could turn probability to her advantage.