i am sure Park knew that his defense had bad aji but i believe the game was too close or black may be down few points.

The review macelee posted states that simply defending on the other side (R2), right at the beginning of the sequence, would have been correct and that White would have "no chance" then.

Are there comments on how far Ch'oe read before initiating the sequence? Myself, it took me a minute to convince myself that black had no hope at the end.

至此中午休息，13：00继续

I rather suspect that not read all the way out (from the start)

but similar to the reasoning/decisions in grandmaster chess when a player decides "with a pawn for the exchange and a strong attack there has to be enough somewhere". And this may be similar with regard to that comment, right or wrong, that defending on the other side would have worked. Just as in master chess where the defense is more difficult (more error prone) than the attack precisely because no time to read out all variations.

In other words, go master level intuition "there is enough aji in the situation that a counter attack must win compensation".

Also at play here the tendency for the other master to "accept the challenge". I bet that the analysis which said that the other side works took too much time and the outcome too close to count "over the board".

I revisited the original game commentary in Chinese. It is not clear who made those comments, but tom.com almost always invites Chinese professionals to make such commentary, or translates directly from Korean sources. The comment says: "at B105 white suffered major losses and black's advantage is clear". The two moves later: "B107 should simply hane [from the other side], and white does not have any chance". These sound like a very strong opinion that black is leading by a big margin.

I wouldn't be at all surprised if the sequence was read-out completely from the start. True, its not a short one, but a lot of moves are forced, so its pretty much only a few branches which need to be read out. It seems like it is on a verge of being readable by me wrt. the sequence length, and what I would be unable to do is (a) get the idea to begin with, (b) find out one or two really surprising moves, and (c) evaluate the end position from that far back. I am very far from a pro, so to a pro this should be doable.

Not to mention that without (a) finding the few really surprising moves and then (b) reading it out to the end (i.e. White can kill something or live inside Black's area for sure) - there is no such thing as "there has to be enough somewhere" since White just gave Black a whole bunch of additional points and removed a whole bunch of potentially game-changing aji. In other words, if the sequence did not work for White, it would be a very bad play.

So, I personally believe the sequence was fully read out. Flashy as it is, it does not seem to be too hard for a Go pro.
Regardless what a chess grandmaster might or might not be capable of.