After Will saves Isla from a watery suicide attempt, incited by the tragic death of her son, the two become an item of sorts, walking around the grounds of Redford's Scientology-like compound together and eventually making a Scooby-Doo-esque trip to a morgue. When they find out Will's father has a new device that can record images from the afterlife, they steal a corpse and test out the lo-fi brain machine on it. Instead of a celestial light show filled with clouds, angels, and harp music, they see a hospital. They decide to investigate further.
Eventually, Thomas ends up using the device and discovering that the "afterlife" takes you to a moment you regret from your life and lets you change the outcome. In his vision, Thomas gets to save his wife (Will's mother) from killing herself. "I always said the afterlife was a different plane of existence," he says when he returns from his trip. "But what if it's a different plane of this existence?"
It's a vision of heaven that spoke to McDowell on a deep level. He and co-writer Justin Lader worked on many drafts of the script, tinkering with the various religious and spiritual implications of their specific afterlife. The "regret" version stuck. "We settled on that because I just hope that's what it is," he says. "As humans we constantly feel moments of regret or wish that we could have done something differently and wish we could go back and change something."