When crito comes to sneak socrates out of jail, socrates says they must first consult an "expert" on matters of justice and injustice to determine if escaping would be just and morally permissable. who is the 'expert' the consult?

The correct answer is truth.

Although we don't know whether or not the real Socrates actually said this, the literary depiction of this philosopher is accurate. Socrates practiced what is called the "elenctic method" (also known as the Socratic method), which, put simply, is answering a question with more questions. By doing so, you can stimulate more conversation and eventually, according to Socrates, find the truth.