From Executive Producer and showrunner. The opening car chase scene was shot in Hong Kong. Stunt Co-Ordinator Jeff Cadiente organised the filming of the stunt.
This episode marked the return of Grace's first episode of filming S4. The first 4 she did was filmed back in April after S3 ended. It was rumoured that she was pregnant at the time of when the show finished filming and at the start of filming S4.
The scenes of Grace & Ian (Kono & Adam) were shot in Vancouver. They turned the streets of Vancouver into Hong Kong for the episode. Grace apparently just had her baby before filmng and wasn't able to fly to Hawaii to film her scenes.
The story that John McGarrett talking about Steve wanting to be a cop like his father that was recorded on the cassette recorder was also mentioned in 1.01 - Ohana (Family)
The coded numbers that Joe found in the cassette recorder that was found in the 'Champ' box was "46, 33, 79, 2, 45, 6, 46, 9"