Yup, that’s how it’s done when there’s a heat exchanger.

However there’s a reason why the boiler room is usually locked off in a 30 story building. Bleeding a radiator might be relatively harmless, but there’s no way of knowing what the pressure is supposed to be without knowing the entire system.

Some (lower) buildings might even have direct district heating without an exchanger, which is absolutely no go to even bleed.