I watched the February 4, 2023 Friday night MMA Bellator 290 Johnny Eblen vs. Anatoly Tokov fight off and on. Eblen appeared superbly trained and conditioned, as did Tokov. They were both so fast that I had difficulty at times seeing the technical details of the strikes, holds and breaks. At any rate, I was surprised to see Tokov, appearing a bit worn with punishment, suddenly catch Eblen coming up from the floor with his back to Tokov in the final round (5) and lock in a guillotine choke on Eblen, who was facing him at about waist level. Within a few seconds Tokov appeared to simply release Eblen, who went on to win the fight in a decision. What did I miss? From my own experience (in fights and witnessing fights in and out of the ring) it is extremely difficult to escape a choke hold, particularly in that configuration (but I am not a grappler really).
Having seen footage of that particular choke, the reason is simple:
He did not have him in a proper choke in the first place.
If you look at the positions, Eblen's neck was on waist height when Topov closed his grip. Accordingly, there was no counter-pressure on the back of the neck and thus no effective choke at all. Tokov would have had to drop (and control the hip with his feet) in order to get Eblen's neck into his axle region, gain control, and exert pressure from two sides. That is pretty hard to pull off when pressed into the cage wall, and that was the position Topov found himself in before he could establish his grip. Instead, he tried to pull his neck up, which he failed at as well.
Therefore, Eblen escaped by keeping his neck low and tight and Tokov's hip pressed against the cage. That way, he made it hard for Topov to exert pressure or even improve his positioning.
Obviously, Topov did lack the skill and/or wind to make the choke happen, realised that himself, and thus let go of it, maybe to have a final k.o. chance.