Are you sure that shooting noisemaker arrows is against the rule? Or rather: Are you sure that making noise without using equipment is different from shooting said arrows? If yes than I'd suggest to throw some junk around or maybe (if one is nearby), step into a cat in order to make it meow; in both cases the guard, should he hear it, would ramp up to half-yellow alert and slowly investigate without drawing his weapon. Throwing junk directly on him might result in a yellow alert but I don't know if that fits your rules.
Without having the location clearly in my head I cannot be more specific unfortunately. Good luck, though. Rutherford Castle refuses being reunited right now, otherwise we'd have it as one map soon.