'About time they found out.'
Adrian wasn't shocked they found out about the guard. He was, in fact, surprised it took them that long. He must have been loitering around the high-security facility for a couple of hours, looking for the boss. Still, it took them another hour to find the knocked-out guard.
'Maybe I should have used Gluttony on him,' Adrian thought. 'That way, they'd have never found him.'
Although it seemed like the right choice, Adrian was there to kill the boss and close the dungeon, not to kill humans. However, he wouldn't hesitate if it came to that. After all, it was better to kill them all than let them cause chaos around him.
'If people find out I did this, it could cause me trouble. Welp, looks like I'll be killing a lot of people here after all.'