All doors lock automatically when the lock side is pressed. They unlock when the unlock side is pressed.
Driver's door

Front passenger's door

To lock all the doors from an open front door, press the lock side of the door lock switch and then close the door.
NOTE
When locking the doors this way, be careful not to leave the key inside the vehicle.
Locking, Unlocking with Transmitter
Auto Lock/Unlock FunctionMazda 6 Owners Manual: Snow Tires
Use snow tires on all four wheels
Do not go faster than 120 km/h (75 mph) while driving with snow tires. Inflate
snow tires 30 kPa (0.3 kgf/cm2, 4.3 psi) more than recommended on the tire pressure
label (driver's door frame), but never more than the maximum cold-tire pressure
shown on the tir ...
Mazda 6 Owners Manual: Canceling Operation of Blind Spot Monitoring (BSM)
The Blind Spot Monitoring (BSM) system can be set to inoperable.
When the Blind Spot Monitoring (BSM) is set to inoperable, the Blind Spot Monitoring
(BSM) and Rear Cross Traffic Alert (RCTA) systems are turned off and the Blind Spot
Monitoring (BSM) OFF indicator light in the instrument cluste ...