Your car has a starter interlock relay that wont allow the starter to work unless the correct key operates the door lock system. The car has an alarm but this relay is controled by the central locking system. IF it happens again try locking & unlocking the car from both doors & the trunk. This might help if this interlock relay isn't getting signal.
The sulfer smell can come from different brands of fuel, also many of the E 420s run on the rich side & short drives can make the smell worse!!
MERCEDES Benz Master Guild Technician (6 TIMES)
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