In the DVD commentary for this episode, director Brian Grant and actor Bruno Langley refer to an additional motivation for Adam's actions. Apparently, in earlier drafts of the script, Adam's father suffered from a disease that was incurable in his time (2012) and he hoped to learn about a cure which had been discovered between that year and 200,000. In the shooting script, the condition is arthritis. No trace of this motivation remains in the finished programme, although Grant discusses it as if it were still present. Langley and Grant also reveal that the "frozen vomit" that Adam spits out in one scene was in fact a "kiwi and orange ice cube".