What is the explanation of this cutscene? Can't get my head around it

I got this cutscene today, and safe to say I'm rather confused. I'm pretty sure that it's a memory of the knight trying to escape the abyss, but the hollow knight managed to reach the top first, and therefore just fell like all the others we see while climbing? I'm not sure if there is a definite answer for this, but my main query is: How did the Knight manage to ever get out of Hallownest after this, I thought the fall would have just killed it? Basically what happened after this scene ended?

I know this has probably been asked a million times i just dont understand this and I really want to because i want to study this game's lore. Thank you to anyone who may leave the answer or (most likely) their theories!