If I’ve learned anything from the Miraculous Ladybug trailers this:

Is just a red herring. Remember when the trailer for Dark Owl hit, and everyone thought Ladybug and Chat Noir would reveal their identities. Or when the trailer for Frozer hit and we thought Chat Noir would reveal his identity?

This is either a dream/fantasy sequence, or Marinette almost gets akumatized, like what happened in Zombizou.

I think she’s frustrated with how Lila is manipulating the entire class, and maybe she tried to prove to everyone that Lila’s a liar, and Lila turned the class on her. So she’s either in the bathroom to calm down, or she’s sitting in there crying.

I could see this going either with Marinette remembering the breathing exersizes that Miss Bustier taught the class, and so the akuma moves on to Lila, since she seems to get akumatized in the episode, and it’ll probably have something to do with either Marinette or Adrien calling her out on her lies).

Or Lila will see the akuma and actively seek out getting akumatized (judging from the season 2 finale, she seems to like getting akumatized), and I have this image of Lila breaking into Marinette’s stall and just grabbing the akuma herself and shoving it into something (I doubt this will happen since I don’t think it’s actually possible, plus Lila gets akumatized outside, I just thought it was a fun idea)