When The Watcher/Joshua sets down the pill bottle on the desk in front of Dr. Chiles, you can clearly see that it is for Zolpidem 5mg. Zolpidem 5mg pills are not white as are seen in the bottle but dark pink, and although Zolpidem overdose can lead to death, it is not a most likely situation, considering that The Watcher/Joshua knows that Stephanie is on her way over and that she could prevent his death with timely medical attention. Also, it is highly likely that Dr. Chiles, with all his medical/biological knowledge, would ingest something that would result in his immediate and definitive death if he were to actually commit suicide, which is what The Watcher/Joshua is attempting to portray.