The Doctor was looking at him and then at Caitlyn "He won't yell when I'm ill, But he does look like he needs to talk about it." He didn't like people having to hold things back from him, especially if they were friends. He looked at Cailtlyn "I would have been more specific there, because his favours can be well ........... , If you get to know him well enough then you would know." he chuckled a bit.
Jack merely just nodded and looked at the Doctor and put a hand on his arm "I am mad at you for leaving me behind, But your my friend and you are ill, I'm not going to yell at you." He smiled a bit and then hugged him. 
He poked him in the chest "But don't think I'm going to let it slide... ," He grinned again.