In a bowl combine beef, garlic, salt, pepper, and oyster sauce. Stir until fully combined and let marinate while you prep the other ingredients.
In a small bowl combine all ingredients for the sauce. Whisk together and set aside.
In a wok heat the oil over medium to medium high heat. Once heated add the chile pepper and green onion. Let cook until fragrant. About 30 seconds. Add the beef. Cook until brown on all sides. Remove from wok and set aside leaving the remaining beef juices in the skillet.
To the hot skillet, add baby bok choy, green onion, red chile, and half the sauce. Cook on medium high until the baby bok choy starts to become tender. About 2-3 minutes. Remove the veggies from the wok and set aside leaving the juice at the bottom of the wok.
Over medium high heat add the rest of the sauce to the pan juices and bring to a simmer. Add the rice noodles and stir to coat the noodles in the sauce and warm through. Cook for about 2 minutes then add the baby bok choy, green onion, red chile, and beef. Stir until well combined and warmed through. Serve immediately.