Decoding this descending run

[rach3pianoconcerto]

Hello

I’d like help trying to decode exactly what Anthony Burger is doing here. It doesn’t sound like a blanket descending chromatic separated by 3rds. I’m thinking theres a lot of show involved and maybe it’s not that complicated. Any thoughts of what’s going on in this clip? Fast forward it to 1:34 where you get to the quick descending passage. Thank you in advance.

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