There

One commentator suggests that the most important word in the opening couple verses of Ezekiel is the word "there." That there, in Babylon, away from Jerusalem, away from the temple, away from the promised land, that God was there. This works against the prevailing understanding in the ancient times that gods were territorial. God appearing there in Babylon dispels this notion (as will the content of the vision to come).

We aren't territorial in our understanding of God, but we do have a complex understanding of his "there-ness." For instance, we pray for the Lord to be "with" someone, but we do this with full understanding that God is already there. So we obviously are asking God to be uniquely with them or with them in a way that they recognize. Apparently, God can be more "there" sometimes than others.