I'm going to look around the room for any other exits that may be around. Not only is Arachnos paranoid, but it makes him feel like he is slightly in control; something he hasn't felt since he accepted this job.
I'm not sure if I get to apply the Specifically Looking bonus (+3) to the check, so I'll leave it out for now.
Perception (6) + Visual Specialization (2) + Intuition (5)
Looking for other exits:
13d6t5 3 [3, 6, 4, 3, 6, 2, 4, 1, 2, 3, 5, 3, 1]