For the sake of argument, let's grant for a moment that the advocates of "tranquility" as the goal of life will quickly accept what they don't grant to Epicurus - that it is sometimes necessary to embrace pain or disturbance for a few minutes - so that they can "get back on the path to tranquility."
So such a person is going to admit that there are times when they deviate from their highest goal, for the sake of getting back on to that highest goal -- but they are going to admit that their highest goal -- in the 70 years out of eternity that they have on this earth -- their highest goal is "to be tranquil.... to be calm"?
Oh my god, if that is what they see as the best way to spend their time on this earth, then either someone needs a new dictionary on the meaning of tranquility, or someone has been tragically led astray.
And I don't think Epicurus needed a dictionary, nor was he led astray. His words, however, have been hijacked.