No suelo ser fan de los videos donde el modulo no coincide con la voz original, pero esta canción tiene privilegios, la amo- y la Miku siniestra queda perfecta
The password hint is the hiragana of the blank space between [不意に出る ] that is listed in the link. Compare the song lyrics and hints. Also, please refrain from asking other people for hints or answers. If you see this reply and still don't understand it and ask around, I'm sorry, but I can't distribute it to such people. This reply uses Google Translate. Sorry if I didn't convey it well.