Tikki pulls the door open, returns the passkey to her belt, then lifts the 
Zeiss goggles over her eyes. A pair of blue laser beams cross the doorway, one at chest-height, the other just below 
the level of her knees. The beams spring alarms if interrupted, but Tikki can 
easily by-pass them. She removes the duster, tosses it between the beams, then 
follows the duster, bending under one laser and stepping over the other. Still 
carrying the duffel bag, she enters the stairwell, then eases the fire door shut 
behind her.