There are two squares you havent even touched...

One has to be opened from where Huche is so you are going loop towards him then keep going down. Referring to your second picture 

i did the same thing, i think it is a bug of sorts. i went left from the upper left then when i got to the door i assumed it was a safe space to stop at, after huche, it is not if you do not complete the path it blocks all the doors again, i believe its a bug, as it should not lock the door again and the other path has portals out along it where as this one reuses portals but suffice to say, you need to bring a team with high enough moral to do the whole stretch through on the left, start over from the top left there.