Sunshine (film)/WMG

The crew had gone insane by the end of the film
Its implied throughout the film that staring at the sun for extended periods is playing havoc with some of the crew's mental stability. As such, to gloss over the inconsistencies with part of the films ending/GenreShift, it would certainly fit with the theme of the melancholic character studies and subtext that Capa (or any of the other crew) had eventually been driven insane by either the futility of their mission or by the sun. This would certainly explain  Anyone who died as a result was either via their own mistakes, or in fighting (as we saw earlier in the movie, some were already at each other's throats), and any references to   was in their own heads. Whether they still completed their mission or failed is down to the viewer -