Confidently thinking that Yuko's group couldn't do anything to him, the long-nosed Transcendent calmly waited for her response.
"I'm afraid we cannot do that." Yuko answered, declining his 'polite' request.
There's just no way to show them the Source Energy core. Among them, only Daisuke or in this case, his avatar, knew about its location.
The Source Energy core was obviously the place where the World's Will of a world resides.
Its location was naturally unknown to its denizen and even if someone's consciousness was summoned to that place, they had no way to tell where it was.
No, it's not in another dimension, it's a tangible place that could be accessed.