Player 1: As soon as the chamber starts, hang a left and place a portal on the side of the ledge and then on the single wall panel located just above on the left-hand wall. Once you’re up beside the red button, push it to drop some repulsion gel onto the floor near the lift.
Player 1: Drop down off the ledge, jump off of the repulsion gel onto the lift and once you rise to the upper floor, press the red button up here to start another flow of repulsion gel near the lift on the upper ledge. Now drop down to the ground floor again, go back in your original two portals and you should now notice the lowered lift just up ahead. Jump off of the repulsion gel and get up onto the lift. Ask player 2 to step off the button to raise the lift you’re on. Once you’re up here look for the encased wall panel, set a portal up here so your friend can nip through the lower portal and join you at the exit!