Hanzo nods and waits, for all he knows Emi-san heard fifteen people and while he wasn't afraid to die in the line of duty, he'd prefer to succeed in the line of duty.  So he'd wait, following her lead, but assuming a defensive posture, they could be waiting in ambush or readying themselves to charge through the door at them, so Hanzo wasn't going to sit idle, he'd remain ready for battle.