Security Pass

Test Chamber 13: Place portals as shown in the image. Use a portal to move the laser sideways and a time portal to send it into the future. Travel through the time portal, potentially taking some damage. In the future, rearrange portals so the laser hits the target. Head through the door.

Test Chamber 14: Travel to the present via a time portal. Summon a reflector cube and position it in the present as shown. Use a portal to direct a laser through the first node and reflect it into the next two nodes. Travel to the future. Use portals to bring a laser into the present through the time portal, ensuring it passes through the node. Retrieve the reflector cube from the future and bring it to the present. Adjust the present reflector cube to hit all three nodes. If necessary, return to the future to retrieve the future reflector cube again. Place the future reflector cube at the end of the nodes to reflect the laser into the receiver, completing the chamber.

Test Chamber 15: Start by going through the particle field to the left. Place a portal where the laser hits the wall and a time portal on the opposite wall. Travel through the time portal to reach the future, bypassing the particle field. On the other side, use another time portal to return to the present. Place a new portal on the upper wall above the laser room to direct the laser to the first receiver. Travel to the future and place a portal on the small wall in the laser room to shoot at the receiver. Return to the present. The laser should be hitting the first receiver, powering an elevating platform. Stand on the platform and shoot a time portal behind the node. This raises the platform, allowing you to summon a reflector cube. Place this cube on the lip above the second receiver. Travel to the future. Retrieve the future reflector cube and bring it back to the present using a time portal in the laser room. Position the cube to reflect the laser into the second receiver through the node. To proceed, get to the other side of the particle field without going through it. Use an existing portal or a time portal to bypass it. Once on the other side in the present, climb the stairs and use a portal on the upper wall to hit the third receiver. Finally, move the reflector cube onto the switch to complete the chamber.