in fact , marisa 'volunteered ' to cover the desk every night that week and , while her grandfather ate , she would steal away and remove the cabinet keys from his desk , and methodically extract an exact measured amount of the horse tranquilizer ketamine through each individual wax vile stopper by syringe , enough that it would eventually add up to the dosage taylor and jesse needed but too little an amount to cause suspicion to the nak*d eye .