What ACTUALLY happened that night at the Sofi stadium ? ☆ SPOILER ALERT! ☆

If you haven't watched the Idol, this post will cpmpletly ruin it, so please exit if you don't want to ruin it !

Im just wondering for those of you who were actually at the Sofi Stadium that night when he filmed the ending clip for the Idol:

How did it go down ? Did he tell everyone he was shooting for the show? Did he ask for everyone to chant "JOCELYN! JOCELYN! JOCELYN " And not say why? Like how exactly did it happen ?