It looked like it was time to have another talk with Dr. Dempsey, a very intense talk. When we'd spoken on the phone, she'd mentioned going back on afternoon shift. She'd also said something about reading some "four A.M. shift report." Add to this fact that health-care clinics generally run twelve-hour shifts. Conclusion: Dempsey 's afternoon shift was probably 1600 to 0400 in the morning. Which meant she'd be getting off duty in-I checked my watch-about two minutes. Would the people coming off shift stay in the building? Doubtful: they'd most certainly want to get home. And would they leave through the front of the building, necessitating unlocking the doors? Again, doubtful: they'd leave by the alley route. Which I was keeping staked out.