Find Roark’s hidden room in Ep. 7: Glass Houses
Battlefield Hardline HOLLYWOOD HIDEOUT Achievement / Trophy Guide
After you planted the bug, you have to go downstairs and get to Roark’s hidden room. Let the first enemy walk by and jump down straight ahead. Crouch and follow the two guys to the end of the room and then left. As soon as they enter the room it’s safe to take them out.
If you want you can also shoot your way there. Look for a hidden panel next to the tv. It’s blends into the wall but is pretty easy to make out. Open the panel and then the secret door to get access to the room.