Set pressure cooker to "slow cook" and add carrots. Place roast into the pot on top of the carrots. Add beef stock, Worcestershire sauce, salt, pepper, and garlic.
Cover and set to cook for 3 hrs. When finished, carefully remove lid and remove the beef from the cooker.
Let rest for 10 minutes, then slice. Layer meat onto the rolls and spread mustard onto the rolls. Use the cooking liquid for dipping. Serve and enjoy.
