Gaia is... A lot of things. Surprisingly complicated as a person and character.
She is more Alien than malicious. She isn't human, and doesn't have human wants, needs, desires, or dreams.
Add on to that, that she is fundamentally flawed, and was broken by her own children... Well, Zeus uses her broken remains as a chair, to put it into perspective. The fragment of a fragment that is Alchemist's patron is childish, whimsical, and does things without thinking about consequences. She isn't cruel to be cruel. She is... in a way, innocent of cruelty. Even though her actions result in cruelties; to her, they are just things she does on a whim. Not to be thought of afterward.
I mean, even in this update, she thought that Alchemist would like what she did. That it would be awesome.
Ignoring the fact that she just sent a person into a place that breaks heroes. Against his will.