With every action, there is an equal and opposite reaction. That was what Hugo had in mind when he came up with the plan of saving the world by finishing Vector off once and for all.
And that notion only made his raving self crave Vector's defeat even more. The man initiated the destruction of the earth. So what would the opposite reaction be?
"Hmph, I knew it!" Vector exclaimed.
The villain didn't immediately flee the scene although knowing that they had set up the trap for him. Instead, he manufactured more Plague monsters and commanded them to surround Hugo and Iron Alchemist.
Hugo set one of the monsters on fire and followed up with the others. But he was overpowered by their large numbers.
The situation was too dire, and the only way to kill them all would involve severe energy waste. In fact, trying to escape in order to avoid energy waste would also be very taxing.