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Rather than "collective action" as the traditional meaning of assembling a group of people, to go against another group of people...consider this:

collective action can be a group of people, taking individual actions, with their own self interest in mind, valuing the individual rights that humans should have. 

In your example, collective action can be a group of people kicking other people off the life raft. The group in this case, does not need to know each other or be physically together...they only need to have a collective thought process, then take a action as an individual. This can still create a collective result.