The tortoise and the rabbit were in a 42 kilometer marathon. The rabbit can run 5 times as fast as the tortoise. Less than halfway into the race, the rabbit dropped his lucky rabbit's foot, and so stopped to try and find it. After finding it, he started running to catch up with the tortoise. When the tortoise reached the finishing line, the rabbit was 2 kilometers away. How far (in km) did the tortoise crawl while the rabbit was looking for his lucky rabbit's foot?