i did this by accident and i believe it has something to do with the door not having time to load, not sure if this would be something considered legal or anything, i was considering running the game myself so i thought it was funny i found this

okay looking into it further it seems that the game does not load doors during autosaving which just lets you run straight through (at least with the agility from taking the agility perk in the beginning) u can take the elevator up to talk to Vela by jumping to the left and then jumping towards the invisible wall and the corner but u can also just skip the whole castle like this which i think would save time after looking at ur runs, im not experienced running the intro and it took me 2 min to get outside the castle and it seems (almost) on pace with u guys (not sure if this breaks something else though)

This is a known glitch, interestingly enough doesn't really end up saving a lot of time. Abusing door loading like this can also sometimes mess up geomatry loading in other parts of the map.