Instructions
Play through the game until you reach the Hilihili Research Facility. Press the "Press for Assistance" button to talk to Dr. Craven. Go toward any of the exits and Dr. Craven will think that you're leaving and he will fall asleep.
Go to Dr. Craven's desk and click on the PDA. Select "Settings" from the top, right corner, then click "Mute" to turn the sound off and prevent the doctor from waking up. Click on the "Employees" tab and scroll down until you see "Fiderman" and take note of his employee number.
Click on the "Lockers" tab and scroll down until you get to Fiderman's employee number. His locker combination will be listed to the right. Go downstairs to the lockers and click on locker 13.
Turn the dial to the right until it lands on "4," then press the green button above the combination wheel. Turn the dial to the left until it lands on "2," then press the green button. Turn the dial to the left again until it lands on "7," then press the green button. Turn the dial to the right until it lands on "9" and press the green button to open the locker.