In a large pot of boiling salted water, cook the beans until crisp-tender, about 2 minutes. Drain, rinse and pat dry.
In a large skillet, heat the olive oil. Add the garlic and cook over moderate heat until fragrant, about 30 seconds. Stir in the vinegar, water, mustard, honey and celery seeds. Add the carrot, parsnip, red pepper and onion and toss until warmed through, about 1 minute. Transfer to a large bowl. Add the beans and toss well. Add a few dashes of Worcestershire sauce and hot sauce and season with salt and pepper. Garnish the slaw with the chopped egg and serve warm or at room temperature.