The rules, yes. That was why people like Marco stayed within what he knew. In his own world, he recognised the boundaries, and he knew the wolves that lurked amongst the flock. In a world he doesn't know, he can't tell the angels from the demons, and that was when he could end up losing everything.
"On call?" he reiterated, the change in the monotonous tone of his voice hinting at a spike in his interest with his new acquaintance.