Who is Mark from Inside Scientology: The Story of America's Most Secretive Religion and what is their importance?

Marc Headley was originally a Messenger in the organization and was the first preclear that Tom Cruise audited. To keep Cruise's auditing on track, Headley was given priority treatment so that nothing could go wrong with the audits of Cruise. Later, Marc joined the Sea org and married Claire, another Sea Org member. However, the two had marital trouble, because they were prevented from having children by the Sea Org and because Claire was higher on the chain that Marc. Claire had two abortions, as part of the common policy for Sea Org members, and the two suffered Miscavige's anger and violence for many years. Clare and Marc escaped Scientology and brought a suit against the church for violations of labor laws and human trafficking, but the suit was dismissed.