Don't blame the TSA on this one. The passengers were screened and inside the security perimeter. And I'll wager all the walkup doors on the jetways are not locked from the outside.
A simple call to 911 would have gotten an airport policeman on scene and an escort for all the passengers to go inside. The captain was looking to Houston dispatch for leadership. And we see how that worked out.
An alternate scheme - taxi to the corporate FBO on the field and deplane. Just takes a little initiative.