Okay but consider: the floor is made of lava reveal. Everyone is milling around the school, minding their own business, and Alya gets an idea. If she says the floor is made of lava around Marinette and the girl has nowhere to go, she’ll have to tackle someone - namely, Adrien - to get off the ground.
Marinette comes over, a bit sleepy, but on time. Alya sees Nino and Adrien. Adrien is yawning, but Alya is certain that he’ll catch her friend. She bides her time, then turns to Mari and is all like, “Hey, Mare?”
Between being starstruck by Adrien and tired from an akuma, Marinette is an utterly unsuspecting victim.
“The floor is made of lava.”
Marinette jerks awake, takes a glance around for something easy, and without a word, books it away from Adrien and is halfway across the courtyard and Alya’s like 1. why and 2. frick she’s fast and all of a sudden it’s just??? Light??? and now Ladybug is there, swinging away with a little vindictive smile and glaring at Alya before her mouth drops and she realizes what she just did.
Cue dramatic reveal, but then Alya’s like -wait, where’s Agreste- and she turns to see a petrified Nino staring at a Chat Noir that’s now hanging from a basketball hoop by the tips of his fingers.
Both LB and CN play the floor is made of lava on a regular basis so it was just gut instinct for them