In a wok, heat oil over medium-high heat. Add garlic and onions and stir-fry until translucent.
Add pork and sear. Add soy sauce, chicken stock, oyster sauce, carrots, celery, cabbage, and sausage to wok. Reduce heat and simmer for 5 minutes or until vegetables are al dente and wok is almost dry.
Drain rice noodles, stir into wok and cook for 5 to 7 minutes on medium-low heat with meat and vegetables.
Season, to taste, and serve immediately on a warmed plate. Garnish with scallions and a lemon wedge.