You should take the opportunity to sleep. You've been driving all day and you didn't get very much sleep last night, either.

[Sherlock will look over his own injuries while she rests. He's gotten quite used to doing that, though he tends to only address the ones in need of immediate attention and chooses to ignore the lesser wounds for the sake of saving time. Joan could probably guess that much about him and how he treats his 'transport' in other aspects of his life.]