>>1932265I'de be careful anon.
I'm planning on doing something similar while bouldering gyms are shut however metal + cold is a recipe for a very slippery surface. Just be aware of your local laws, get an idea of how good their security is and don't do anything retarded that'll create excessive risk and you'll be fine. You can also do some smaller climbs to gain some confidence before attempting a big one
Pic to prove i have some experience