(1) 3일이면 끝나 버릴 걸 (가지고) 그렇게 모두 걱정하고 있었어요.
=> We were all so worried about what turned out to be only three days' work.
=> We were all dreading unnecessarily what could be done in three days.
* -ㄹ 걸(것을) (가지고) = with/about something that ...; when it was going to be ...
(2) 그사람이 그렇게 빨리 풀려 날 걸 (가지고) 신문에서는 그 사람이 사형당할 것으로 보도되었어요.
=> The newspapers reported he was slated for execution when in fact he got release in such a short order.