What's the room of a medical staff only enter to it to rest and eat. Can I call it 'staffroom'? (I saw on Wikipedia that it's more for teachers' staff.
I can only answer for the UK. The term staff room is commonly in use for a room provided for the medical and other staff to relax and gossip. It may also have food and drinks. The term doctors mess is also used, here is a link to one in the south of the UK http://www.sghdoctorsmess.co.uk/. I would expect that if such a facility were restricted to a specific grade of staff it would be called, for example, the consultants' mess as saying the consultants' staff room seem a bit tautological. (Consultants in the UK are the highest grade of registered medical practitioners. Whether in these more egalitarian times they still have separate facilities I do not know, it is some time since I worked in a hospital.)