The "dunker" is the part which most dread - especially for non-swimmers. Personnel not only have to practice escaping from a dummy helicopter lowered in to a tank but also have to escape from the module when it is capsized.
The shots inside were taken by undergoing the process a number of times and very hit or miss and using a torch wrapped in a sandwich bag for lighting.
Some video footage was done using a Hero sports camera and the results were edited to fit with an appropriate piece of music - "Extreme Ways" - the theme music from the Bourne Ultimatum. A bit of self-indulgence.