Yes and no. I don't think anyone is capable of understanding the exact nature of Jesus and how the divine and human were interconnected.
Did he pray to an external entity or to something within his body?
Yes.
Does not prayer establish an order - subordination?
Yes, it does.
Philippians 2:3-11 3 Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. 4 Let each of you look not only to his own interests, but also to the interests of others. 5 Have this mind among yourselves, which is yours in Christ Jesus, 6 who, though he was in the form of God, did not count equality with God a thing to be grasped, 7 but emptied himself, by taking the form of a servant, being born in the likeness of men.
8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. 9 Therefore God has highly exalted him and bestowed on him the name that is above every name, 10 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
That is what some term ‘dangerous theology’. When you imply that the human part of Jesus had to pray to the ‘god’ part of his, and if he had to do so through external acts such as prayer, it denies the total intimacy between the two ‘parts’ - that external acts of supplication had to be performed to communicate between the two ‘parts’
The mechanics of the entire thing would also make the human part as crucial as the ‘god’ part. And the trinity would have to rather be termed the ‘quadrinity’ to give full credit to the importance of the human part.
By the way, what happened to the human part?