(a) A lawyer shall not reveal information relating to representation of a client unless the client consents after consultation, except for disclosures that are impliedly authorized in order to carry out the representation, and except as stated in paragraph (b).

(b) A lawyer may reveal such information to the extent the lawyer reasonably believes necessary:

(1) to prevent the client from committing a criminal act that the lawyer believes is likely to result in imminent death or substantial bodily harm; or

(2) to establish a claim or defense on behalf of the lawyer in a controversy between the lawyer and the client, to establish a defense to a criminal charge or civil claim against the lawyer based upon conduct in which the client was involved, or to respond to allegations in any proceeding concerning the lawyer's representation of the client.