If your vehicle rapidly closes in on the vehicle ahead because the vehicle applies the brakes suddenly while you are traveling in headway control, the warning sound activates and the brake warning is indicated in the display. Always verify the safety of the surrounding area and depress the brake pedal while keeping a safer distance from the vehicle ahead.
Additionally, always keep a safer distance from the vehicles behind you.

Mazda Radar Cruise Control (MRCC) Display Indication
Setting the SystemMazda 6 Owners Manual: Front combination light removal/installation
Caution
Incorrect servicing of the discharge headlights could result in
electrical shock. Before servicing the discharge headlights, always refer to
the Discharge headlight service warnings. (See DISCHARGE HEADLIGHT
SERVICE WARNINGS)
Note
When the ignition switch is turned to ON, ...
Mazda 6 Owners Manual: Audio Operation Using Voice Recognition
Voice command
When the talk button is pressed and the following command is spoken, the audio
or navigation can be operated. The commands in the () can be omitted. The specified
name and number are put into the {}.
Standard command
Communication (phone) related command
Entertainment (audi ...