OK, so the buzz about "the hallway scene" brought me to this movie and then to this board.
Given the impact of this scene, I guess in hindsight I would have preferred to be unaware of it, but that didn't make it any less effective. I loved it, and certainly understand why it's so talked about. I will say this, however:
Crucify me if you must, but the greater reason this scene was so effective had little (not nothing, but less) to do with what happened, and more to do with the already-present anticipation of something horrific, and an impeccably timed surge of terrifying music, catching the viewer completely off guard. One might say (well one might not, but I might) that the same thing was achieved in Stanley Kubrick's The Shining in a peaceful scene with a mother and son, followed by a crash of horrifying music and a blank screen that simply says "Tuesday". It had no relevance to the story, as the E3 scene did, but it was effective nonetheless.