What happens if the MAD button is not acknowledged within 10 seconds after the tones begin?

If the MAD (Message Acknowledge Device) button is not acknowledged within 10 seconds after the alert tones begin, the emergency brakes will apply. This safety feature is designed to ensure the immediate attention of the train operator and is a crucial part of the train's operational safety systems. The activation of the emergency brakes serves as a fail-safe mechanism that prevents potential accidents due to operator inattention or incapacity. The system is engineered to prioritize the safety of passengers and crew by bringing the train to a stop if the operator does not respond in a timely manner.

In the context of the other options: the system does not reset, the alert does not stop, and the train does not continue without incident when the MAD button is left unacknowledged. Each of these scenarios would compromise safety, which is why the emergency brake application is the definitive action taken by the system in such instances.