“do you see what they are doing.” This is a rhetorical question. God is emphasizing the evil by formulating what He says as a question. He is building a case and showing Ezekiel why He has to leave His Temple.
“so that I must go far away from my sanctuary.” The last sight of Yahweh as He leaves His Temple and Jerusalem is Ezekiel 11:22-23, when He is over the Mount of Olives. We know He goes from there into the east, but exactly where we are not informed. In the Millennial Kingdom, He will come back to His Temple from the east (Ezek. 43:1-4).