@Jom Spoiler it seems that we have to walk on the metal half pillar and slide it sideways to reach the other side. While returning back, those pillars make B unstable and make B fall out of the level. It happened twice, I gave up.
@I_am_Bot thanks. I might give it a go, but if you kept falling, I don't hold out much hope. It's a shame though because the rest of the level seems good.
Fell at first then found safe way to cross the organ. My way was slightly different from video. Did it shorter moves.