RTO,
Bring the aircraft to a stop, apply the parking brake, ensure forward idle on the thrust levers and .......... wait.
Check the reason for the stop call, confirm it between ALL flight crew and then commence memory items/communication as appropriate.
For engine fire and emergency shut down the fuel cutoff switches must be selected to cutoff before the fire handle is pulled.
So, the shutoff valves and pylon isolation would have been completed once the aircraft was stopped.