When Laura Roslin's family were killed, her grief led her to a public fountain where no-one, not even Laura would be able to determine which droplets were from her tears, and which were from the fountain. When Billy died, she wanted every drop accounted for. So she braced herself against the bulkhead and unleashed her tears and grieved. She didn't care that Admiral Adama was still in the morgue. In fact, she wanted him there. Wanted him to know he was the reason for those tears. It was an act of intimacy that demonstrated trust as it exacted punishment.