He will sit there quietly until he sees both engines turning, then will expect a disconnect.
No he won't. He will tune out and not be listening to anything and still get run over. The only thing he needs to hear are the statements set out in SOPs. What the crew need to do however is ensure that
someone has said "Clear to disconnect" and that
someone has stated "Sighted with the pin" before any After Start checklists are completed and a clearance to taxi is requested.