1 - Not really sure abt that, cos in the final moments (seen as a flashback) if u see, the timestamp in the right corner, there was a glitch for abt 8 seconds, before the bomb explodes. But when it was being shown in real time, it showed that Kara was going to stop the bomb from exploding. So another twist and mystery there.
2 - The mystery man it seems is John Nolan, uncle of Christopher & Jonathan Nolan (who has appeared in the Dark Knight Trilogy as a Wayne enterprises board member). I dont thnk he was playing any game with Kara at the time, so we will have to wait and see what his intentions are.