guys can we keep it calm.
My guess going by the pictures is that the heaters are powered at set times so shouldn't need turning on manually very often, and the boost is probably only for if it's really cold outside those hours.
Most modern buildings tend to run warm rather than cold, especially if they're like flats because they tend to be quite well insulated and most of the heat everyone produces from just being there works to help keep it warm. I wouldn't be surprosed if much of the time you're going to be more worried about being too warm.
Rewiring a heater that is wired into the wall in the halls is not a great idea as you'll likely be working with a live connection, and if found out could result in being kicked out of the room due to the safety issues bot to yourself and everyone else.
Hooking up a heater to one of the sockets in the room may also not be a great idea, especially if the halls have a rule against it because depending on the wiring the halls may not be set up to allow for that, so if several people on the floor do it they may end up tripping a breaker which will make you very popular with the other students affected) especially any who are working on a normal PC at that time) and whoever has to reset the breaker.
You might be able to get away with a low power heater (I had one that was 500 watts), but it would be a case of being very careful with it's placement and use.