I am pleased to hear I could be of assistance, of course. [And he means it. Sebastian enjoys being useful.]
Those who subscribe to the idea of the inherent value of every life will disagree with this, but... [he shrugs lightly, gently (and finally) giving her back her arm,] personally, I see not the point in arguing whether someone is right or wrong in how precious they deem any one life. You master presumably considers your life too valuable to trade for anyone else's, and I would not consider him more wrong in his opinion than you-- nor more right.