If you mean the door in the keypad room - there is a way, keep looking!
If you mean a different door (and there is only one other door you could mean) then it doesn't open.
Viewing post in locked door
theres the door in the very first area and i dont jknow how to open it. i found a key in the button room and i see a vent on the ceiling above the giant button. how do i open the dooooorrrrrrrr the key wont open the door in the beginning. is there even a way to get up to the vent? or is the button pointless
edit: NVM I FOUND IT LOL