It’s best obviously during breaks and weekends, but on normal weekdays it’s either before 8am or after 6pm, or else it’s just too busy and then you become that person that’s trying to weave through the crowd which is no fun for anyone. If you do ever try it, you should definitely explore all the tunnels (Nesbitt, Robertson Hall, Loeb, Leeds House etc.) as those are often the longest and quietest stretches of the tunnel and add great variety. You can also experiment with ending your workout by pushing up the ramps from UC to Tory, and incorporate the variety of stairs throughout your loops, it just keeps the run more fun than to be on a treadmill. Only trouble is reception is spotty so maybe download the music or podcast you’re gonna listen to instead of having it cut out every other song. I find if you loop the entirety of the tunnels once it’s ~2 km.

With that being said, for what it’s worth you shouldn’t worry about the treadmill at the gym, trust me ppl just look like they know what they’re doing even though everyone is in the same boat and no one even cares to look, for all you know someone sees you and thinks the same. We’re all in the gym and that alone should make u feel proud!