While Nathan gives Will his daily physiotherapy, our wheelchair-bound hunk asks Lou what she does when she's not working. The answer is unsurprising: she reads a lot.
Nathan then gives Will ten bucks. Huh? Turns out they made a bet on the boringness of Lou's life. Lou is surprised by how much this hurts her.
Lou confronts him about this later in the day. Will sticks to his guns, telling her that she's "letting [her] life slip by" (15.33). She should be doing something to make her life better, like going to night school so she can follow her dreams.
Will ends up in the hospital two days later with an infection. Given some time off, Lou joins an internet forum for people with spinal injuries under the name "Busy Bee" (15.77).
Lou makes a post asking how to cheer Will up and is shocked by the number of responses. There are a few that seem to support his desire to commit assisted suicide, but most are enthusiastic and compassionate.
Will looks exhausted when he gets back from the hospital. Lou takes him on several more trips, with varied success.
On the way home from a wine tasting, Will and Lou somehow get on the subject of tattoos. Neither of them have one.
Impulsively, Will tells Lou that they must get tattoos. Tonight.
So they do. Lou gets a bumblebee on her hip (because of course), while Will gets a tattoo befitting his sardonic sense of humor.
It reads: "Best before: 19 March 2007" (15.164). That's the day of his accident.