This method is for large cuts of meat that need to cook slowly to tenderize them, not small pieces that cook up very quickly, as pork tenderloin does. Think brisket, or pork shoulder. Besides, your pork tenderloin will serve one hungry person each. There will be no leftovers.
If you meant pork loin, that is different. It is so lean it should not be well-cooked. I trim the sinewy membrane from the outside (and stew that to tenderize it, dice and put into soup) and roast the meat to an internal temperature of 155°F or so.
When you do cook brisket or pork shoulder using this method, don't forget to cover the pan.