its multicrew and they(pax) are part of it. So when u have an emergency you need to speak to them to let them know whats going on and whats the plan. we had a explosion in the toilet with a few people getting injured. we had to reassure the passengers that everything was been looked after ie emergency services on the ground etc..
I think multicrew is more than just the two in the front.
Also the one non flying does all the radio calls and talks to cabin crew etc...