Gamzee took Calliope and Caliborn and placed them in the troll session’s ectobiology lab. It might have been to give them a roof over their heads, something he didn’t know they could do without.
But there’s more.
The lab meteor is where Gamzee and his friends were created.
Where they contacted the kids, leading to the creation of the Green Sun, and the retrieval of Lil Cal from the void, into Dave’s dream room.
Where they spent three years en route to the new session...
It’s where the new population was created through ectobiology, and if Kanaya had stuck to her original plan, where the Mother Grub's new breeding caverns would have been located.
It marks both the start and the end of several races and universes.
The fitting location for a Lord of Time to grow up, all in all, especially one who ordained the annihilation of one of those races and two of those universes.