It is for now, but we still have access to the entire island and at least part of the ocean. It'll do in a pinch- the Core's energy readings are strong enough that we wouldn't even have to be on top of it to monitor its behavior. To do anything lasting, we'd have to be below ground, but for now, we'll just have to take what we can get and sort the rest out later.

[Until she figures out how to burrow underneath the diamond...]