You might as well ask an artist to explain his art, or ask a poet to explain his poem. It defeats the purpose. The meaning is only clear thorough the… - Rick Riordan

You deal with mythological stuff for a few years, you learn that paradises are usually places where you get killed.

"Nico strode forward. The enemy army fell back before him like he radiated death, which of course he did.
Through the face guard of his skull-shaped helmet, he smiled. "Got your message. Is it too late to join the party?"
"Son of Hades." Kronos spit on the ground. "Do you love death so much you wish to experience it?"
"Your death," Nico said, "would be great for me."
"I'm immortal, you fool! I have escaped Tartarus. You have no business here, and no chance to live."
Nico drew his sword-three feet of wicked sharp Stygian iron, black as a nightmare. "I don't agree.

Jumping out a window five hundred feet above ground is not usually my idea of fun. Especially when I'm wearing bronze wings and flapping my arms like a duck.