The OS will always be SEooC so never in 'full control' of safety. 'Safety related' would be more accurate than 'safety critical' and more in line with the common understanding of the phase.
As I understand it, this means that Linux could only ever be considered a safety-related *element*, but surely it could still be part of a safety-critical *system*?
However, I agree that 'safety-related' might be a better term to use in general, as it applies to a broader range of use cases for Linux.