In The Crito dialog, Socrates is awoken by Crito early in the morning, the day before the old philosopher's execution by Hemlock poisoning. Why is Crito there?

Crito was there to try to persuade Socrates to escape from the prison where he is awaiting execution.

Explanation:

Socrates was accused of "corrupting the young" and "impiety" by the people of Athens and kept imprisoned awaiting execution by Hemlock poisoning. One of his friends, Crito, a rich wealthy Athenian visits him the day before he was to be killed. He had already bribed the guards and even made ready a boat for his escape to another town. But Socrates refused, saying that even though his charge wasn't right, he doesn't have to pay back evil for evil, in his case wrong for wrong. "Two wrongs doesn't make a right". Injustice should not be answered with injustice. So, he'll happily accept the verdict of the people of Athens and be executed.