Unlike Nの／Vている間 presented in Lesson26-6-1 , Nの／Vている間に indicates that the action/event takes place sometime during the time. Therefore, the words which express continuous action(i.e., action in progress) or state cannot be used with …間に.
The following are some examples which cannot be used after Nの／Vている間に.
×待っている(be waiting), 食べている(be eating), いる(be; exist[animate]), ある(be; exist[inanimate]), ねむい(sleepy), しずかだ(quiet)
I went to the bank [and came back] during lunch break.
Let's put things in order here while the baby is sleeping.