What's stopping Santos from snitching on Langdon?

So, in the interest of plot twists, drama, and mess -- what's stopping Santos from snitching to the hospital admin herself that Langdon was stealing drugs from the hospital/patients, not just suffering from an addiction?

Is it just her allegiance to Robby, or the fear that he would rather continue covering for Langdon and sell her down the river instead (especially since at this point, he would go down with Langdon for covering for it for so long). Is it something that is more feasible once Robby is out of the hospital for his sabbatical, you think?