So God chooses to obey the morals that exist separately from him?
No, God, by definition is a Maximally Great Being. As an MGB, He acts at all times according to His own nature. The very reason we are able to claim that morality is objective is because it stems from the perfect, immutable character of God.
This implies that he's unable to exist or act within our reality.
I agree that the claim Christians often make about God's relationship to time is rather non-sensical.
If we understand time as simply a measurement of change and/or duration, and not a thing in itself, then the notion of God somehow existing "outside" can be discarded.
But this topic is supposed to be about abortion. And whether or not you agree with our view of the morality of abortion, the reason we hold to abortion being immoral isn't difficult to understand.
1. God created all human beings with inherent moral worth and value.
2. A new human being comes into existence at fertilization.
3. Killing an innocent human being for convenience sake is immoral and wrong.
4. Unborn human children are innocent.
5. 98.5% of abortions are committed for non-medical emergencies. Or put another way, 98.5% of abortions are committed for convenience sake.
6. Therefore, at the very least 98.5% of abortions are immoral and wrong.
Now, whether or not you disagree with all the premises, the view that Christians hold with regard to the morality of abortion is consistent and understandable.