During Chris's (Henry Ian Cusick) sermon at church near the end of the film, the real Chris Williams can be seen in the audience, seated on the front row.
The car crash, as depicted in the film, was recreated in the exact location in Salt Lake City where the real crash took place (on February 9th, 2007) and was done so convincingly that an actual news crew was sent out to report on the scene. Additionally, signs had to be put up to warn/inform local residents, no doubt remembering the event from before, and much to their relief, that the scene they were witnessing was fake and had been created for filming purposes.
Chris Williams is actually a member of The Church of Jesus Christ of Latter-Day Saints.
Chris Williams was a bishop in the church at the time of the accident.
'Just Let Go' was edited and color graded in Apple's Final Cut Pro X using the Color Finale plug-in.