Back when I was a freshman at UE in 1985/1986 school year, a friend and his cousin and I went tunneling. We entered at the Engineering/Science Building and exited at the Union Building. It was pretty fun though. The tunnel we were in followed the front circle which starts with the Engr/Sci bldg then goes to the old library and then to the admin hall, then to Hyde Hall and finishes at the Union building. There were several turns you could make that went to other parts of campus but we never took the opportunity to look.
When we got under the admin building, there were many phone lines and unused coaxial cable that was going to be used for the futire network. We looked at it but left it alone. There were some side rooms and I picked up some magazines and instituitional catalogs that were back from 1969-1970. I took them back to my room and looked at them. It was pretty interesting seeing the color patterns and especially the hairdo's on the women modeling in the pics. My friend's uncle went to UE during the 1960 and we saw some old papers like grade cards that were filed away. He was able to find one of his uncle's grade cards which had an F for one of his classes. He took the card and took it home and showed it to him. His uncle laughed.
We steered clear of the library since it was rumored that there was an alarm system hooked in. This was a time when the new library was being built. We finally exited at the Student Union Building at the North Stairs in the basement. We non-chalantly walked out and walked back to our dorm rooms. We noticed Campus Security was standing at the front door of Union and steered clear of them. We overheard their radios mention something of looking for people tunneling.