First, inspect the room.
Read the paperwork herein, then turn around and go through the other exit into the cave system. Push the door open, and you'll see that you're in Farley's Community Center.
Toggle the door again, then go through the stone arch. Walk all the way down and through the purple portal again.
Continue down the path, then left into the building and through the portal. Keep going through, then turn right, and head back to the seed-swap device. Activate it.