The cut scene of the sun rising in fast motion (midway through their 48 hour shift) is actually a shot of the sun setting in Norfolk, Virginia that is played in reverse to make it look like a sunrise. Look closely and you can see the cars are going backwards.
The character Alex (Justin Chambers) wasn't in the original pilot, so his scenes were filmed later on and in re-shoots.
Alex Karev is the first one to refer to George O'Malley as '007.'
In this episode Cristina tells Meredith "If you want to be a shark, be a shark." In episode 2 season 14, Meredith tells Jo the exact same thing.
Originally, the writers and creator wanted Ellen Pompeo (Meredith Grey) and Isaiah Washington (Preston Burke) to be a couple. Ellen vetoed the suggestion because it too closely mirrored her personal life. Ellen is married to Chris Ivery.