“I couldn’t have gone into medicine,” Cohen said quietly. “My mother died of breast cancer when I was a kid. As far as I know, she had good medical care. Everyone did everything they could. No one was to blame for what happened to her.” He swallowed. “And in a bizarre way, that was part of the problem for me. She was taken from us so young, yet there was nowhere to lay my anger or hurt. It was as if I had no retribution for her loss.” He looked away, embarrassed. “I’m not making any sense.”

“I know exactly what you mean, Seth,” Lopez said softly. She reached over and touched him gently on the elbow. “I went through the same when Papa died.” She paused. “It was so unfair. Like I was cheated, you know?”

“Exactly,” Cohen said, pleasingly aware of her fingers resting on his arm. “I think that’s what got to me about the death of our witness, Carol Wilson. She kind of resembled my mom at the end. Young, but so gaunt and pallid. I was with both of them when they died. But in Carol’s case, I knew someone was responsible. Someone who could be made to answer, you know?”

She nodded and squeezed his arm gently, before pulling her hand back.

Though he inferred a pleasant intimacy in her gesture, Cohen felt self-conscious for having opened up to a woman he barely knew. “How about you?” he asked. “Why medicine? Why epidemiology?”

“The medicine part is easy,” she said with a chuckle. “It’s in my blood. Both my parents were doctors in Guatemala, but neither of them could get licensed in America. Papa was a surgeon in the old country, but he ended up as a radiology technician in Phoenix. He made it pretty clear from as long as I remember that his only child was going to be a doctor—come hell or high water!”

“And why epidemiology?”

“It seemed so cool to me when I was a med student. The outbreaks. The exotic bugs. The travel. The drama. And best of all, no night call!” Her tone took on a serious edge. “And the scale of it appealed to me. I had this kind of naive idea that if I did my job right, instead of having an impact on just one patient I could make a difference for many.” Her face flushed. “I think I must have a hero complex or something.”

Cohen smiled, admiringly. “Seems to me you are making a difference now.”

“Don’t know if the stats would bear you out, now that MRGAS has hit L.A.”

“That’s hardly your fault.” He wanted to provide better reassurance but was at a loss for words. Instead, he said, “Lina, do you think Dennis Tyler is still spreading this infection?”

“Not sure he needs to anymore. It might be overkill.”

“I don’t follow.”