For all you Law & Order SVU fans. I need help with a cetain half missed episode.?

Okay, I was almost finishing a certain episode of L&W SVU, it was about a pedifile that had gotten away with mutiple killings and s. Well, the SVU team caught up with him at the train station, then he slit Olivia's throat and Eliot decided to help her instead of the boy. Well, the boy ends up dying and he leaves with the girl. Eliot and Olivia end up in a certain abandoned building and all of the sudden, Eliot is held hostage with the guy and olivia is on the ground pointing the gun at the pedifile, then it went to commercial and I had to go to bed. If anyone has seen it, honestly, please tell me what happens, it's been on my mind all day. Thanks.