Add apricot preserves, thyme leaves, ¼ cup of water, and red pepper flakes (to taste - start with a pinch, taste, and add more if desired) to pan, and mix well to combine. Return pork medallions to the pan and bring glaze to a simmer. Cook for 5-6 minutes, turning once, until mixture is thickened, pork medallions are glazed, and a minimum internal temperature of 160 degrees is reached. Remove medallions and any glaze in pan to a clean plate and set aside. Wipe out pan and return to heat.