Wash and peel the shrimp, leaving the tail intact. Heat the water and chicken broth, adding the bergamot leaves cut in half, the lemongrass stalks cut into diagonal sections, the galangal pieces, and the fish sauce. Let it boil for 3 minutes. Reduce the heat and add the shrimp, the onion thinly sliced, and the mushrooms to the broth. Let it cook for 5 minutes. Add the peppers, the tomato cut into dice, and the lime juice. Let it cook for another 5 minutes. Serve the soup hot, sprinkled with coriander leaves.