뛰어가다 is running off somewhere — away from you, or over to something. The -게 slot supplies the manner word: 신나게 (gleefully), 빠릿빠릿하게 and 발빠르게 (quick on your feet), 이렇게 (like this, usually with a demonstration). 왜 그렇게 뛰어가요, 'why are you running like that', turns up twice here.