Cut baby bok choy in half vertically, from top to bottom. Rinse and dry well (a salad spinner is good for this).
Heat wok over a high flame and add 2 tablespoons oil. When the oil is hot, lower flame and add garlic slices. Stir-fry briefly to soften, but do not brown.
Add bok choy, increase flame, and stir-fry for about 2 minutes. Add the salt and chicken broth and cover pan. Steam for about 1 minute and check doneness. When cooked through but still crisp, plate bok choy.
Mix oyster sauce, vinegar and soy sauce in a bowl or measuring cup and heat in the microwave for 20 seconds (or heat until warm in a small saucepan). Drizzle sauce over the bok choy and serve.