“It was the other way around: lead-212 and bismuth-213, actually. But yes, I did mention those isotopes, and now I have to go back and check to make sure they were the ones being used. I really need to leave.” Pia checked her watch. “Oh my goodness, it’s almost six o’clock. I promised to be back by six and it’s a forty-five-minute subway ride up to Washington Heights.”

The MEs could sense Pia’s acute anxiety. No one was convinced by her display of surprise at the time.

“I think you need to stay here until we get to the bottom of this,” Laurie said. “You might have been exposed yourself. Alpha emitters are dangerous if either ingested or breathed in. There might be other people who need to be checked out.”

“Thank you so much for your help,” Pia said nervously, looking at Laurie and Jack but not quite looking them in the eye. She was itching to get away. “I can be in touch about the isotopes tomorrow.”

Pia didn’t want to be trapped there when the MEs called the authorities, which she knew they would do shortly. She had to finish this on her terms.

“Young lady, what’s going on?” Jack said. “You show up with a Geiger counter in a shopping bag and bruises on your face. Are you a medical student at all? Who sent you here?”

“No one sent me,” said Pia. “I can see how this must look, but I am a medical student. You have to trust me—no one else was contaminated, I’m sure of it. But I can’t stay here, I have to get back, I’m sorry.”

Pia started backing toward the door, and Jack stepped toward her.

“You can’t hold me here if I want to leave,” Pia said. “And I want to leave. Right now!”

Laurie touched Jack on the shoulder, and he paused. Pia turned and walked away quickly. Chet followed and looked back at Jack, puzzlement written on his face. He had no idea what to do. He didn’t even have her cell number. Pia and Chet disappeared. Maureen was confused too, wondering if she should call security.

“She’s right, Jack, we can’t keep her here. She said she’s at Columbia, so she won’t be hard to find.”

“If she wasn’t lying about that too.”

Part of what Jack and Laurie liked about their work as MEs was the unexpected. This was something very new.

“What do you make of it?” Laurie asked.

“I dunno,” said Jack. “There’s a lot she isn’t saying. She suspected there’d be radiation in the bodies. Of course she did, she brought her own Geiger counter! But when she found what she was looking for, she was completely spooked. More like terrified.”

“Definitely,” Laurie said. “We need to get someone to track her down.”

“I agree.”

Jack thought for a second.