As a reviewer, you have an obligation to maintain the confidentiality of the submission that has been sent to you for review. While Dr. Mills has discussed the research openly, it is not clear if the content of her talk was identical to the content of the paper. You are free to talk to colleagues about the content of Dr. Mills’s talk, but you should not show them the paper without her permission. At the same time, if this is a single blind review process (in which the reviewer’s name is not disclosed to the author), it is not appropriate for you to contact Dr. Mills in your capacity as a reviewer. You can reasonably contact her, however, and ask her if she has any papers relating to her talk that you recently heard. If she sends you a copy of the paper you are reviewing, that indicates her willingness to share it.