 There's a hidden door locked behind a code under the Arasaka Tower. Stay tuned to find out how you get in and what's actually in there. So at the Arasaka Tower Memorial site there's a hidden door locked behind a code. To enter the door use the code 2023. This will unlock the door for you to enter. Now inside you will find names scrolling on the glass. These are actually the names of the developers who worked on this game. Poor little Easter egg.