The DUNBAT Trophy
Story related, can't be missed
You will get this trophy when you first reach Theta.
In this area you need to flip a switch in the server room before moving on. It's in the basement. There's a blind enemy patrolling the server room. Just turn off your flashlight, give it a wide berth and don't step on anything. Once you flip the switch the monster will come running. Hide behind the nearest server and wait for it to leave, you need to hit the switch again within a certain amount of time. After flipping it again you can leave. Carefully.
Back upstairs, use the other door and go down the hall then right and another right after opening the door. In this room you can find two chips you need to advance. Take the smaller one into the opposite room and plug it into the computer. Copy the Scan Room Environment to the chip.
Back in the first room, plug in both chips and select Brandon Wan as your simulation. Choose any combination. After a few failed attempts, Catherine will mention you're missing something. Go back to the hallway and right. Go through the TV room and into the hallway full of bedrooms. Enter Brandon's (Catherine will unlock it) and look at everything. Eventually you learn about Alice. Go back to the computer and choose "Scan Room" and "Alice".