Interrogate
There were several courses of action that he could take. The first one was, of course, the most straightforward course of action. He could just storm in and start interrogating the people running the show.
But the odds were high that that would alert the target of his mission before Rui actually reached him. First, he would be assuming that the people there were actually aware of the location of their ringleader. Second, even if they were aware, he needed to be careful of how he extracted the data from Faraday's men. It was risky.
Even if he killed all of them after interrogating them, there was a high chance that Faraday would find out about the leak and would immediately scram, making Rui's job even harder.