Unit with "bonus" room, has egress, but shares a wall with garage

[Matthew Sidlo]

There is a Rhode Island multifamily building that has a 1 bed/1ba listed as one of the units.  It includes a finished bonus room (300 sq ft that has egress).  *The room shares a wall with the unit's garage and has a fire rated door that goes into the garage. There is an additional door that connects the room to the unit. 

Why wouldn't they have turned this into a bedroom?  

Before I go to the town... I'm wondering why it might not be allowed to be a bedroom. 

It has egress, would I be able to rent it as is?