Professionalism. You don't see that every day. The "thugs" patrolling the Hideaway are an exception.
It is of utmost importance if you're going after treasure here, not to be spotted—not at all. The occupants will whisk away their goods at even the hint of an invader.
That said, make good use of the secret passage. It is lightly-patrolled and a good place to "lie low" if things get too tight.