Monygham's prophetic remark fits well with this suspenseful scene, full of prophecy, death and foreshadowing. But if we read "treasure" to mean "character" (as Monygham implies above), then the remark might have a larger meaning. In that case, "the curse of death" could mean mortality itself, and the message is: the only satisfactory bargain we can make with cruel life is to be ourselves as much as we can. The doctor's sarcasm would come from his own history, in which he feels that he has betrayed his own character.