"Some people can't achieve tranquility in the near term, but that does not mean they are any less Epicurean in pursuing the best mix of pleasure and pain that is available for them at any particular place or time."
In saying that I am thinking back to the recent thread on "Whether one has to be well off to be an Epicurean" (or a title something like that - I will find it and link. - Here it is)
I think it's a significant problem that many people get the idea that one has to be rich or successful to be an Epicurean, and I think what we are talking about now is related to that. One can be very upset and energetically engaged in some very difficult behavior that no one would call "tranquil" and still be a good Epicurean. In fact I would say that a person who in appropriate circumstances DOES NOT forgo tranquility in favor of vigorous action is the one who is not the good Epicurean (again, the "diving into the stream" example in AFDIA).