We'll pretend "
Cyber Jar" is being Flip Summoned for this demonstration....
P1 Flip Summons "
Cyber Jar", activating it's effect.
P2 does not respond to this effect.
P1 does not respond to this effect.
Resolve "
Cyber Jar"s effect.....
1. Destroy all monsters on the field and send them to the Graveyard.
2. P1 (Turn Player) picks up 5 cards, showing all to P2, and chooses orientation of valid monster cards to be Special Summoned. (one of these happens to be "
Hero Kid", it's effect is triggered now.)
3. P2 picks up 5 cards, showing all to P1, and chooses orientation of valid monster cards to be Special Summoned.
4. All other cards picked up go to the hand of the respective player.
5. End
Cyber Jar resolution.
Now even though 2, 3 and 4 'seem' to be resolving at different times, they are considered by the game to happen at the same time, so the last thing to happen is still the Special Summoning of a monster. Since "
Hero Kid" was one of the monsters Special Summoned by this effect, it's effect will trigger, activate, and resolve w/o issue.