Greetings, I don't know if this really is 'working as intended' but I didn't see anything in the sort, but you know the sprinting treasure chests in WSG? I haven't tried in AB or EoTS but if you activate darkflight, it stacks on top of the sprinting. So if you have the flag, you can really gun it out of the tunnel and pick up some great mileage and your still sprinting. Possible further exploitation is swiftness potion after it wears off. If it's working as intended, I am sorry for wasting your time.