Learning the truth led Joe, Stein, and Malcolm to burst into "More I Cannot Wish You." Their positive responses may have been a ruse for their children, but it was win-win for us hearing them sing.
After convincing Iris and Mon-El to tell the truth, Barry accompanied Iris home, and learned not only was Joe her father, so was Stein! Needless to say, Barry's shocked reaction led the men (and Iris) to jump to the wrong conclusion about his motives. Barry reminded them that he loved musicals.
Of course Iris, Joe, and Professor Stein are likely there to perform rather than save the superheroes from their musical prison. It's hard not to love the stylish looks of this villainous world.
Judging by the lighting, this looks like it's happening in the speed force. The last few times Barry met Joe's doppelganger, he wasn't a huge fan of the speedster. Will he have better luck with this version?
At first glance, it seems like Iris and Joe are seeing Barry off as he enters the speed force. But it's doubtful Barry's leaving from what looks like the police station. He may already be inside.
Ramsey: You know, I don't understand you Barry. You march towards death without fear, just like mum. Where is it you get your strength? Barry: Probably the same place she did, people I love.