The rear armrest in the center of the rear seatback can be used (no occupant in the center seat) or placed upright.

WARNING
Never put your hands and fingers around the moving parts of the seat and armrest:
Putting your hands and fingers around the moving parts of the seat and armrest is dangerous as they could get injured.
Split Folding
Head RestraintsMazda 6 Owners Manual: Storage Compartments
WARNING
Keep storage boxes closed when driving: Driving with the storage
boxes open is dangerous. To reduce the possibility of injury in an accident or a
sudden stop, keep the storage boxes closed when driving.
Do not put articles in storage spaces with no lid: Putting articles
in storage sp ...
Mazda 6 Owners Manual: Operation
NOTE
The engine may not start and security indicator light may illuminate
or flash if the key is placed in an area where it is difficult for the system
to detect the signal, such as on the dashboard or in the glove compartment.
Move the key to a location within the signal range, switch ...