Fast track, depends on the security queues, have never seen the priority lines enforced.

Escorting requires you be a VVIP (with EK office placing a note on your reservation to get a staff member to meet you) or have reserved the Marhaba service for transiting (for $$). Note that VVIP means you're either A-list celebrity, have a HRH/HH title or be guest of the ruling families/airline.