The short tunnel leads you to another gallery pictures, although these pictures are much larger than those in the previous room. It may take a moment to look at all of them. A portal stands near the tunnel's exit, so you can go back to the main room of the tower without walking through the tunnels that lead you here.
A small sign hangs on the wall directly across from the tunnel entrance. It reads:
Go into the other room.
Go back to the Icon Tower.