[Sano doesn't say anything to that, because there isn't anything he could reply to that. Instead, he gives Sousuke's shoulder a gentle slap - into the uninjured part - and stands up.]

It's okay to be a bit selfish sometimes.

[He finally says and turns to smile at Sousuke.]

Don't stay too long, or the others will get worried.

[Waving his hand in a casual bye, he starts walking towards the exit.]

And lock up when you leave. I don't want Filch anywhere in here.