In the episode 'A Study in Pink' of the first season of Sherlock the victims are poisoned when forced to choose a pill from the two bottles as confessed by the cab driver. However in the earlier scenes the victims are shown to be picking a pill from the bottle which had multiple pills (3-4 pills). But when the cabbie forces Sherlock Holmes to choose from one of the bottles then each of the bottles had 1 pill only.
Did the serial killer played different games with all his victims and Sherlock or the victims did not really have a choice as all the pills may have been poisonous. Why the number of pills were different?