In a frying pan over high heat, mix water, stock, and 2 tablespoons of soy sauce. Bring to a boil and simmer for 2 minutes. Remove from heat and set aside.
Divide shallots and carrot into four portions. Lay a portion on one end of each schnitzel and roll up to seal the filling inside. Arrange beef rolls with the seam-side down in the simmering stock. Cook over medium heat for about 6 minutes, flipping once, until fully cooked. Transfer the rolls to a plate and keep them warm by covering with foil. Place eggplant halves gently in the fragrant stock, cut-side down, and cook for 4-5 minutes until they are perfectly tender.
Steam bok choy and choy sum over simmering water until just wilted, about 2-3 minutes.
Slice the beef rolls into quarters. Arrange the eggplant, bok choy, and choy sum on plates. Top with the sliced beef rolls and finish off by drizzling with the remaining soy sauce.