Clean and season shrimp: Devein the shrimp, keeping the shells on. Season with the chopped chadon beni, ginger, garlic, salt, black pepper, lime juice, and pimento peppers. Mix well, cover, and refrigerate for at least 30 minutes.
Sauté vegetables: Heat oil in a large pan over medium heat. Add the scotch bonnet pepper and sauté for about 2 minutes. Add the bell peppers, carrots, onion, and celery. Cook for another 2–3 minutes, stirring occasionally.
Build the sauce: Add ¼ cup water, some of the ketchup, and the soy sauce. Stir to coat the vegetables and cook for about 5 minutes, until the sauce thickens slightly and coats the vegetables.
Add the shrimp: Add the seasoned shrimp along with any marinade from the bowl. Stir in the remaining ketchup and water. Cook, stirring occasionally, until the shrimp turn pink and are cooked through, about 4–6 minutes depending on their size.
Taste and serve: Taste the sauce and adjust the salt if needed. Serve hot with white rice or your favorite side.