Is the wage of a security guard working in a usurious institution considered unlawful (haram), even though he does not directly engage in usury?

It appears that the work of the aforementioned institution is based on lending with interest (riba), and therefore, it is not permissible to assist it in any way, as it constitutes cooperation in sin and aggression. Similarly, the wage for guarding it is unlawful. You are obliged to leave your job, unless you are in a dire necessity, in which case you may remain for the duration of the necessity, while diligently searching for another permissible source of income.