Open the Safe
Head to apartment 904 once you get the DVD from the man in apartment 901. Zoom in on the DVD player and push the eject button. Place the DVD into the DVD player and the zoom in on the television for a closer look. Pick up the remote control and use it on the television. Pause the video, using the remote, as soon as Tom enters; he will show you the code for the safe in apartment 909. Head to this apartment now, select the safe and enter the code you just acquired, "45890." Look at the photograph of Tom and Sarah and then take the dossier.
Acquire a Vehicle
Go to the bedroom in Sarah's house when you have obtained the yang lock piece. Zoom in on the box next to the window and use the lock piece in the center slot to start a puzzle. Complete this puzzle using the solution "C-1-1-2-2-C-C-C-3-3-C" to get the car keys. Go to the garage, start the car with the car keys and look at the GPS to leave the house.
Reveal the Trap Door
The storage room, accessed via the reading room, has four empty light sockets on its walls. Place your light bulb in the bottom-right socket to reveal the red card; pick this item up. Now place the light bulb in the next three sockets, in any order, to light different sections of the room. Collect the items described on the card when they are revealed in the light. Take the Shiva painting that is hanging on the wall, too. Put the bulb in the top-left socket and select the Shiva figurine. Attach the Shiva picture to the frame and then put the three gems from your inventory next to the white one. Now position the gems in Shiva's arms in the following order: white in the top-left, blue in the bottom-left, green in the top-right and red in the bottom-right. Go back to the lab and pass through the trap door.
Escape From the Generator Room
Pick up the handle then use the sledgehammer to smash through the damaged wall. Attach the handle to the control box and then pull it. The grate will open, giving you an escape route. Go through the open grate to escape.