Continuity mistake: When the nurse is giving Liam Nelson the address of the investigator, in one shot she's writing the note with her left hand, and in the next shot, she has the pen in her right hand.
Continuity mistake: In the scene when Liam Neeson wakes up from unconsciousness following his car accident, the nurse writes something on her notepad with her right hand, but in the next shot the pen has suddenly switched to her left hand as she puts it into her pocket.
Continuity mistake: The original taxi (with number) is parked outside Gina's apartment complex and they use it to escape, but it went into the river during the accident and Gina's taxi owner boss laments about it early in the movie.
Continuity mistake: The password needed to access Leo Bressler's hard drive, Umbellularia californica, is visible in the book. In the next shot 'umbellularia' is incorrectly typed into the password box as 'umbellurlaria', yet it gains access to the drive.
Answer: Because the killers need to make Liam Neeson's death look accidental. The police think Neeson is crazy, and is not telling the truth when he claims Liz is his wife. The police simply think that Neeson is mentally ill and so dismiss his stories and allegations as untrue. However, if Neeson is then found murdered, there is the possibility that the police think Neeson might have been telling the truth, investigate, and foil the villains' plot. Therefore, Neeson must be killed to stop him investigating - but he must he killed inauspiciously, so it looks like an accident, so as not to make the police suspicious. Thus the poison in hospital - hopefully it would be put down as a standard non suspicious hospital death. And the drugs in the car park at the end of the film are deliberately mentioned by Professor Rodney Cole as being essential in making Neeson's death look an accident. Cole says that Neeson will seem to have killed himself with heroin and so will not consider his death suspicious. So basically these elaborate ways of killing are in order to make Neeson's murder seem an accident and so not make the police investigate.
swordfish