I used to walk through that tunnel often during my rambles downtown during the early-to-mid-'80s, before I moved to L.A.; there was a clean restroom down there, and as you ascended through the stairwell leading to the street exit above the east end of the tunnel, beneath the parking structure, there was a spot where the exit door was locked against anyone on the far side, and a long echo-chamber of steps behind you, out of sight, creating a perfectly dry, warm, SAFE spot to smoke a jay, had one had been so inclined.
I'm glad the sculpture is still there.
Another case masterfully solved by SHERLOCK GODDAMNED MORIARTY.