The code to unlock the door at the top of the stairs in the Delta Beta frat house is "PICASSO".

The code to the safe is "1873". You can find it on the desk in the room you enter from the window. Examine it closely with the woman.

Use the code "EINSTEIN" to hack into the computer and get the ingredients for dynamite. Note: When you break the soda machine in the basement (first level) of the hospital, keep the soda. It is the last ingredient you will need.

Use the code "FREUD" to open the door and get to Jun. This will be the second door you discover.

Use the code "MOZART" to get in while playing as Mei. This will be the first door you discover. To find it, have Mei search with the decryption device.