You could cook them in two separate pans on the stove top, then place them in the oven at the same time. If doing it that way, you may need to increase cook time just a couple minutes (use your thermometer to guide you). Alternatively, if you don’t want to use two pans, you could sear all 4 pieces of the tenderloin in the same pan, then place them on a baking sheet in the oven. Just remember that the ones you seared first might need to be removed from the oven first, so as to not overcook.