V + 다가는 is used to show that if an action is continued there will be a negative outcome:
하루 종일 게임을 하다가는 눈이 나빠질 거에요.
If you keep playing computer games all day your eyesight will get worse.
술을 많이 마시다가는 여자친구와 헤어질 거에요.
If you keep drinking too much your girlfriend will leave you.
너무 격렬한 운동을 하다가는 몸이 아파요.
If you exercise too vigorously, you'll injure yourself.
이렇게 시간을 낭비 하다가는 시험을 잘못 볼 거에요.
If you keep wasting time like this you won't do well in your exam.
지금 남자친구에게 전화를 하다가는 후회하게 될 거예요.
If you don't call your boyfriend now you'll regret it.