There are apparently underground passages connecting the hospitals on University Avenue and all the way to Queen's Park TTC station. I couldn't find a map or even many references to its existence. This Instagram post is the most I could find, but it's unclear if it's open to the public, or how to get there.
Anybody here has experience with it?
Not open to the public from what I understand.
The tunnels were also painted because they transport children from the sick kids ward between buildings. This help with the tunnels not being as scary for younger children.