The next chapter of our Control guide contains a walkthrough for a side mission called A Matter of Time. You will learn, e.g. how to solve the clock puzzle in the motel and how to escort the medic.
To start the mission: go to Sector: Containment, and proceed to Logistics.
Walkthrough: Travel to Logistics. Once you enter the area, go to the left side of the room, in the direction of the United States map. You will hear the voice of Horowitz calling for help - go upstairs and talk to the man. Pull the string three times, and you'll appear in the familiar motel.
The key to solving the mystery is to study the clock at the reception. When you press the bell it will strike the hour - go to open rooms and set the clocks according to the same pattern. You will know that you have set the correct hour after you hear the characteristic sound.
After you solve the riddle, take the key from the reception, and open the door at the beginning of the Motel. Come back to real world - you'll enter Sealed Threshold Corridor, a completely new location. Find the medic and talk to him.
Medic has level 9 access, so he'll be able to open further doors for you. Escort him and fight the enemies along the way. When you are stuck in front of the gate, climb the bricks to reach the ventilation shaft, jump off at the other side and open the gate.
Escort the man until you leave the threshold area. Go now to the Logistics and further to the wounded Horowitz. Unfortunately, the man has turned into a beast possessed by the Hiss. You have to defeat him, which shouldn't be too difficult. Talk to the medic - you'll finish the mission and automatically begin another side quest - The Enemy Within.