muse A and muse B are roommates. muse A is taking a shower and muse B needed to fetch something from the bathroom. so, finding the door unlocked, they sneak in to grab whatever they need. seeing no problem as the shower screen was so fogged up from the steam that nothing could be seen through it other than a shadow.
however, as muse B goes on their way out the doorknob becomes stuck. and muse A gets out of the shower, only to find that muse B is there and they're locked in the bathroom together for however long.
muse B is in their pyjamas, or more so halfway getting changed into them, and muse A has morning but their towel.