Because pork tenderloin is incredibly lean it is really important to let it rest after it is roasted. I think it is better to let it rest for a full 10 minutes on a nice heavy platter with foil over it. That will ensure that there will be carry-over heat that will continue to cook it through. See above about internal temps. When you cook meat the muscle fibers (yes that is what meat is, sorry to burst your bubble if you didn't know that) denature and seize up. If you were to cut into the meat right when it came out of the pan and those fibers were still taught, then the juice held within would flow right out onto the carving board. Resting allows the muscle fibers to relax again and the juices stay inside when the meat is sliced. Rest smaller cuts of pork, such as pork chops that are 1-inch thick or less for 3 minutes. Thicker cuts, such as this Easy Roasted Pork Tenderloin and Apple Skillet should be rested for longer. Up to 10 minutes. Pork loin roasts can be rested for 15 to 20 minutes