I had no problem understanding that he was sucked in, though the sound of it always sounded to me like his body scraping on the metal of the tube (can't listen to it now because I'm at work). But visually it truly looks like he simply falls down to the bottom whereupon he is sucked into the tube. Wookieepedia agrees with me (cue Wookieepedia accuracy criticisms, but the point is that enough people have read that article and not altered it). I also have talked about this with family and friends many times throughout my life, and there seemed to be a common understanding. Being sucked into the side is more realistic to me in many ways, but I wish it were visually more apparent now.