darth_ender said:

Being sucked into the side is more realistic to me in many ways, but I wish it were visually more apparent now.

I have no idea why people think this. It's patently obvious that he gets sucked towards the side when he's falling. The sequence, aside from the flipped shot which Ady is fixing, is shot perfectly clear and makes total sense the way it is. There is one shot from above seeing Luke falling away, then we cut below to him falling towards us, then there is the clear shot of him being pulled towards the far wall and into the vent. It is as visually apparent as it can be.