Oh dear. Apparently it was in fact just as bad. He gives Serph's hand a little squeeze in sympathy, covering it with his other as well. It sounds terrible that someone would simply let someone else kill them, but-- well, if you thought they had a good reason...

There is not a good reason Jack can think of that would make him want to kill Serph, so he says, "That is one thing I can promise you I am not going to do. Okay? I do not kill people." A quick pause, then, "Well, the werewolf might try, but not because of anything like this. Did he not even tell you why? Your officer?" That doesn't seem very fair.