"The Eye" please explain. (meant for people who have seen the movie "the eye")?

okay, i just saw the movie "the eye", it was an amazing movie, but thats beside the point. at the begining of the movie, the lady with blonde curls at the coffee shop (when she [sydney] was with her music teacher), what did she have to do with anything all i know about her is that she jumped on syd, and said "Don't think i wont do it" repetitly. i know the comcept of the movie, how anna wanted her to save all the people, and what her eyes did, but that part doesnt make sense to me, did a miss something, or was it just a suspensefull moment that has nothing to do with the movie, and the man in the elevator, that was in the corner (and dead) and wen she started to go up, he was floating and had a deformed face, was he just a suspensful moment too?? i understand the little boy, and the lady sharing a room with her. but i just dont understand those to moments in the movie. please explian.