Lost could at any time request specific portions of Rowan's memory and it would be delivered to him; this process was fairly automatic because he was still part of Rowan's mental space.
He did not like retrieving memories from Rowan's mind because it was usually packed with excessive information. Rowan did not receive inputs from his surroundings from a singular source, instead, it was from a myriad of sources, and a single second of his memory was jam-packed with so much information that if it was to be written in a book, it would fill up a million thousand paged book.