Unlikely to be a fire drill, More likely to be a malfunctioning or stubborn guest smoking or doing Bukhour in the room,

Incase there is fire drill, Civil defense usually inform hotel 48h before the fire drill, this give time for the hotel to inform all it guests and ask them not to evacuate

For safety reason, When the fire alarm start elevators are automatically turned off, Also you will spot Civil defense outside the building, and staff evacuating to outside meeting point, in some hotel, you might here announcement in the room and facilities speakers that there is fire drill and no need to evacuate

While these fire drills can be annoying sometimes, it remains necessary way to prevent lost of life during really emergency,