In order to have time to fit in flashbacks from the brothers' lives, we decided to project them over the top of the drug taking scenes, to also add to the surrealism and "high" heroin produces for the 2, with the projections being memories but ones they're seeing, and imagining out-of-body, much like the surreal scenes from Trainspotting.
To do this we filmed the scenes first on Tuesday, edited them on Tuesday night through FCP and then played them through a laptop connected to a projector over the actors' performances on Wednesday.