Oh I don't think there was an over reaction Jourdain.
Until the facts could be established, they had to assume he was not acting alone. He could have been blocking the front entrance before the main attack at the back.
Maybe he was delivering the breakthrough plan on the English Channel migrant farce to an expectant Mr Sunak and was overwhelmed by the enormity of the moment.
Of course he may just have been a bit *** and forgot how to park.