here is the answer
Slim Poet says: "Each time an opponent makes him lose a life point, you may discard a card from his hand" and then Wild Bill says: "If your opponent draws or discards a card from your hand or in play with Wild Bill your opponent's AC is the target of a Bang!" This seems like it happen until Slim Poet dies or Wild Bill's hand is empty. Is that right?
Not exactly. Slim Poet ability reads: "...you may discard 1 random card from his hand". This means Slip Poet could choose not to activate his effect at a certain moment.
Hope this helps