Expedition egg rewards, and bringing back to main save question.

[💎 Andy 💎]

Hi.

Iv been doing some Googling / Reddit, and YT research, and am really confused.

If you get an egg as a milestone reward.
How do you take that pet back to your main save?
If the expedition is being run from my main save.

I read that you can get the egg from the quick silver vendor after completion of the expedition.
I also read you can transfer it via the expo/main save slots.

But to do either, do I hatch the egg in the expedition, or leave it as an egg?

Thanks for any help on this puzzling point.