where to go? (gourmand)

https://preview.redd.it/dvnyhsp5vnfh1.png?width=2158&format=png&auto=webp&s=059adc49eb814b3b26801602c9a5a8816b7f78a9

!im playing gourmand and im at the shelter near to the leg, and i swear theres no way through? like i cannot go right at all. the map here shows a tunnel going downwards (in the room thats directl left of the writing "THE PRECIPICE") but that tunnel doesnt exist?!<

!also you can say spoilers, i have finished all the campaigns in the game but it was many years ago so i forgot everything lmaoo!<

!my normal route to 5pb would have been like climbing up the wall that i found on my first playthough, or the other route that goes really deep into the leg, but i randomly found this while wandering around and am so confused, thanks!<