There are 3 occasions in Mark where jesus withdraws to pray due to crisis. This is however not the only instance of prayer. In crisis since he is fully man and fully God who or what would he be praying to. Essentially it would be to himself in some sense of the word.
5 Have this attitude in yourselves, which also was in Messiah Yeshua,
6 Who, though existing in the form of God,
did not consider being equal to God
a thing to be grasped.
7 But He emptied Himself—
taking on the form of a slave,
becoming the likeness of men
and being found in appearance as a man.
8 He humbled Himself—
becoming obedient to the point of death,
even death on a cross.
9 For this reason God highly exalted Him
and gave Him the name
that is above every name,
10 that at the name of Yeshua
every knee should bow,a
in heaven and on the earth
and under the earth,
11 and every tongue profess
that Yeshua the Messiah is Lord—
to the glory of God the Father.
This sheds some light on your question, I think. But also consider that when Jesus fed the 5,000 he said a prayer and blessed the food. We also see Jesus telling us how to pray when the disciples asked him about it and he gave the Lord’s prayer. So we can see there are times for prayer outside of just crisis.
This is an interesting question. The answer is in the doctrine of the Trinity. Although Jesus is fully God (the Son) there is a distinctness between Father, Son and Spirit. We see this in all the gospels but quite significantly in the gospel of John. Jesus is praying to the Father and not to Himself. He says that He only does what the Father wants Him to do and only says what the Father wants Him to say. Jesus, therefore, acknowledges that He and the Father are one (John 10:30) but that they are also separate persons (eg. John 20:17). Hope that helps a bit.