느라고

Because I was busy doing that

Explains that being occupied with one thing led to something else, usually a cost: my heart was pounding from bringing it, you're so busy doing other things, it's still cooling, she really had to slow down for me. Both halves must share a subject, and the outcome is normally a strain, a delay or a failure rather than a benefit. 느라 is the same thing with the ending clipped short.