"Killua fell to his knees, the grief just had hit him.. they were lying, they had to be..? How could he have died!? It wasn't true. There's no way In hell that his father was dead.."
Tsuna just wanted to see the reaction of the weirdos- I mean friends and family around him when he tells them that he is "pregnant". But things escalated quickly and went out of control... out of control as in worldwide out of control.