If he does appear I want Saten, Uiharu and Kuroko to be in rhe dream helping Mikoto then all of a sudden dream Touma appears in his biribiri vision look and falcon punches something out of existence, talks with the girls while giving Saten ammo to troll, giving Uiharu weird fantasies and enraging Kuroko to new levels than all of a sudden he dissapears to go help somewhere.
All of that could be done in one chapter.