Unfortunately, they're also strictly off-limits. Utility tunnels are most commonly referred to as steam tunnels because their primary function is to transport extremely high-temperature steam from a central boiler to all the buildings of the campus. The tunnels also conduct cold air, electrical wires, telephone lines, network connections, and natural gas. The administration policy is normally that students caught in the tunnels will be suspended or expelled, and non-students are threatened with serious fines, but instances of tunnellers being seriously punished are few and far between. If you are caught, you may be able to get off with a warning.
Minor injuries are a possibility.
Be sure to watch out for low overhangs, unshielded pipes and steam leaks. Asbestos may be a concern in some tunnel systems. At least one flashlight and several beverages per person at the minimum. If you have the chance, acquaint yourself with the aboveground layout of the campus, and bring a map of the campus along if possible. This will help you determine where you are when underground.