The Space Elementalist wanted the item Grey showed them at the start, the core that could heal his current wounds. If he can lay his hands on that, he wouldn't need to spend a long time in seclusion trying to recover, he would recover instantly and fight against Grey even.
Grey didn't know the plans of the Space and Water Elementalists at the moment, his eyes were on the five people who wanted to join the battle. If he added the Water Elementalist to it, it would make them six.
Even with that number, he still showed zero fears. Without the Space Elementalist, he didn't need to fear anyone here. Even if ten more people came, so long as none of them was above the Fifth stage of the Elemental Venerable Plane, he didn't have any fears.
This didn't mean that he wasn't wary of some of these people. He didn't know their abilities, and if it's something that could stop some of his abilities, then he would have a tough time.