Reimu was about to lash out, but something made her hold back for now, and watch the imps instead.  She didn't know why she felt this way, but she had learned to trust her instincts at times like this, and she wasn't about to start ignoring them now.  Besides, she told herself, there should be plenty more imps to hunt down if these manage to get away.  So, she decided to follow them at a distance, and try to remain hidden, at least for a short while.