> Try and cross together the energy-sensing and hearing to sense if Marisa, since this is her style, is coming back here for the sack or going elsewhere.
> If she is coming back her emaining mostly-hidden by the shelf-side have our Danmaku-Aim ready to be steady&shoot to fire&nail her, especially within the zone around the sack, when
we catch her at her most difficult angle to dodge our attack before she spots us.
> If she is not coming in this direction, try and set a sort of pattern to her "trail and match it , as far as possible, to the "patrolling rounds" of the fairy maids in the Library, to deduce if right now, or soon, she could be come across one at a loc. we know.