He 'kept/maintained his cool' [=he didn't get angry or upset] even though it was clear that he was being unfairly treated.
He was struggling to 'maintain his cool/composure'. [=he was struggling not to become angry or upset]
They barely had enough food to 'maintain life'. [=to make it possible for life to exist or continue]
(..) Then maybe it doesn't matter after all. The guns they give you are real guns? Real guns. That's incredible. Negative acceleration at . So long as you maintain passenger comfort. Don't you want to listen? l heard it the last time. This is Delos Control to Station . (..)1973 Westworld