Combine egg, steak sauce, and garlic powder in a shallow dish. Place crushed crackers in another shallow dish. Cut tenderloin crosswise into 1/2-inch-thick slices. Pound or flatten slices with the heal of your hand to 1/4-inch thickness. Dip each slice first into egg mixture, then cracker crumbs, turning to coat. Heat 1 Tbsp. of oil in a large nonstick skillet over medium heat until hot. Add half of pork slices and cook 4 to 5 minutes per side or until browned. Repeat with remaining oil and pork slices (or use 2 skillets at one time).