The two points are related, but only indirectly.
Socrates/Plato argues that it would be unjust for him to escape because he has lived his whole life according to the laws of Athens, and even gone to war to protect them -- in short, he has enjoyed their protection from the time he was born -- so it would be hypocritical for him to reject them now that they demand his death.
Socrates/Plato turns his argument against harboring a fear of death into a summation of his entire philosophical program. As he put it in The Apology: "To fear death, gentleman, is no other than to think oneself wise when one is not, to think one knows what one does not know."
Socrates/Plato attacked this kind of assumed knowledge throughout his entire adult life, and it was essentially this conviction that led to...well, to his conviction.
)
In the Crito, he also makes the classic argument usually associated with Epicurus: "death is that which is, when we are not".
In other words, when we are dead, we will not know we are dead, so there is nothing to fear.
(Of course, people don't fear the state of being dead, they fear the process of dying: growing weak, losing dignity, the pain of it, etc. But, while that is not exactly beside the point, it is not something Socrates/Plato contends with. He returns quickly to the theme of rejecting assumptions about things in the absence of any proof.)
So, I would write about the ways in which The Crito is an expression of the consistent nature of everything Socrates/Plato thought and argued.