He does a small test on Ruby.

Just as Weiss showed up, and berated Ruby for the explosion she blamed Ruby for causing, and Yang said, "Wow, you really did explode," Jaune took the opportunity to write, "The next time everyone else has their backs turned, Ruby Rose will lift her skirt to show Jaune Arc her panties, and will consider it normal and fun to do for that moment.

He put the Note away, when everyone was called to the cafeteria to have lunch, causing a distraction. Jaune, not expecting the Note to work, started to head there too, when Ruby tapped his shoulder and said, "Hey," I got something to show you..." When he turned to look, he gaped as she pulled up her skirt, blushing and smiling as he got an eyeful of her white with pink dots panties. Then she let her skirt drop and walked off, humming, leaving him stunned.

That didn't just happen... Did it?