Grey and the others could not involve themselves with the battle with the Half God Plane experts' battlefield, they were focused on the task at hand, which was surviving their current opponents. Grey's act of moving around the battlefield might look very easy, in truth it was not. One mistake and he would not only lose his life, the others would be thrown into chaos as well. His presence is the only reason the Gnomes were not making use of their Puppets, their greatest tool in battle. Without it, although they were still fierce, they were not as threatening as when their Puppets were present.
If Grey leaves the battlefield, these Gnomes would all take out their Puppets and make the lives of those from True Dawn harder.
Grey was moving across the battlefield in shocking speed, helping whoever he could, while also making sure he was not caught by the Peak Sovereign Gnome chasing after him.
