Before the particle accelerator explodes, the power goes out in Barry's lab, and the lights from the buildings visible through the window also go out. When Barry watches the explosion, the buildings' lights are on, and go out only when the energy wave reaches them.
Warfarin has long been a main ingredient in rat poison, and is also used in a more pure form as a pharmaceutical for blood clots; however, it takes three to five days to take effect, and the dosage must be calculated very carefully to balance the actual thickness of how much blood versus the medicinal efficacy of the warfarin ingested. In addition, it has side effects, but hallucinations and excessive sweating are not among them.