-(으)려고 states an intention and 그러다 stands in for 'do that', so the pair describes someone in the middle of intending: 먹으려고 그러는 걸 'he was about to eat it', 왜 자꾸 이방인 힌트를 찾으려고 그러지? 'why does he keep trying to find the Outsider clue?'. -(으)려고 하다 means exactly the same; 그러다 is the colloquial stand-in for it. Most of these lines are questions, often faintly accusing — 야동 찾으려고 그러죠?!