Protests In The Talmud

In the spirit of all the protests going on in Israel, Pshita, claims to have found the one case where a demonstration is mentioned in the Talmud:
תענית יח עמ' א

שפעם אחת נגזרה גזירה על ישראל שלא יעסקו בתורה ושלא ימולו את בניהם ושיחללו שבתות

מה עשה יהודה בן שמוע וחביריו הלכו ונטלו עצה ממטרוניתא אחת שכל גדולי רומי מצויין אצלה

אמרה להם עמדו והפגינו בלילה

הלכו והפגינו בלילה

Soncino surprised me by translating as follows:

For once it was decreed that the Jews should not occupy themselves with the study of the Torah nor circumcise their children and that they should desecrate the Sabbath. What did Judah b. Shammua’and his colleagues do? They went and took counsel with a Roman Matron with whom all the prominent Romans were wont to associate. She advised them, ‘Arise and raise an alarm by night’.They went and raised the alarm by night thus, ‘O ye heavens, are we not your brethren? Are we not the children of one Father? Are we not the children of one mother? Wherein are we different from every other nation and tongue that ye make harsh decrees against us?’ Thereupon the decrees were annulled and that day was declared a festive day!

How did we get from the hebrew מפגין to "raise the alarm?" Tosfot explain the word הפגינו as meaning "Crying out" so I guess soncino might have based his translation on tosfot. I've searched the internet for the source of the word "Hafgana", but have not found anyone having written about it. Is it possible that this talmudic story is the source for our modern usage of the term?