From her vantage point, all Pia could see were people barging in through the door. The place was being invaded—she must have seen twenty people dressed in gowns, hats, masks, and booties rush toward the biosafety unit. Bringing up the rear was a pair of gurneys sprouting IV poles with plastic bags of IV fluid slapping against the metal poles, pushed by more gowned-up figures. The gurneys disappeared into the biosafety unit, whose door had been propped open with a doorstop. Pia felt a terrible sensation growing in the pit of her stomach.

One man stopped by Marsha’s desk and stood next to the terrified secretary, who had a hand clasped over her mouth; another blocked off the entrance door, which was again closed, denying access to the corridor and the rest of the medical center. The laboratory staff crowded into the center of the room and there was a ripple of loud conversation and shouted questions.

“Is this a drill?” Lesley said. “What’s going on?”

The figure by Marsha’s desk pulled down his mask. He was a fifty-something African-American man with skin as black as ebony; his voice was calm yet commanding.

“Okay, folks, this is not a drill. We have a situation, and I need you all to stay right here, right where you are. Is everyone in the lab accounted for?”

People looked around, checking for coworkers among the fifteen or so technicians and support staff standing around. Pia could see the maintenance man in his coveralls standing at the back of the room, gaping like everyone else.

“Everybody here? Okay. My name’s David Winston. I’m from hospital security. These other people are a mixed group from the hospital ER and the Department of Infectious Disease. I’ll give you more information when we have it. I am asking you to please remain in this area. Thank you for your cooperation.”

The staff stood in small groups and talked among themselves. Pia, unable to stay still, walked around in a small, tight circle. Whatever was happening, she knew it wasn’t good. A wave of anxiety washed over her.

The lab door opened abruptly and a tall, distinguished-looking man walked in quickly and made his way through the cordon toward the biosafety unit, conspicuously avoiding eye contact with anyone. He was dressed in protective clothing like the others except his mask hung down on his chest. Under the gown was a suit, not scrubs like the others. Pia knew this was the chief of Infectious Disease, Dr. Helmut Springer, as she had attended several lectures he’d given during second-year pathology.