You've noticed this door from the very beginning but now it is time to put all your clues together to escape.
It seems like you need to select the correct symbol combined with the correct button count for the correct door code.
Don't forget the message you just deciphered!
You remember these images from earlier...
"O my Goddess, stretch Yourself over me, that I may be placed among the imperishable stars which are in You, and that I may not die"