Sebastian would wait a moment, staring up at the open door to make one last positive check before heading down the stairs after her. A few times he'd stop and just glance back up the stairs. The door really got to him. The fact that they hadn't heard or seen anything since the alarms, and then the sudden door being ajar was enough to cause him to be rightfully paranoid over it. He'd run into Talia when she stopped, having tried glancing up one more time. He'd back up a bit. "I'm sorry. What is it? Why'd you stop?"