(MAJOR SPOILER) Wouldn't the end twist have been better if...
... Neville hadn't killed Michael in the elevator just before breaking into Laura's room?
The fact that he and Michael were in the elevator together, you saw one kill the other through Laura, and then Neville breaking in made it obvious he was the killer, thus making his monolgue pointless.
If Neville had just turned up normally as she was expecting, started telling Laura about Tommy's motive as normal, then her realisation that something was wrong with him would have made Tommy Lee's speech alone be the giveaway - would have been more chilling I think, as we the viewers slowly realise along with Laura that he is the killer.
As it plays in the film, Tommy Lee's speech is only there to tell Laura's character he is the killer, as we the viewers already know it!