1d20 + 4 ⇒ (13) + 4 = 17
Once again the large ghoul dodged Abroshqualmie's bouncing ball of fire, but it was distracted enough that Bob got some good blows in with his crystalline blades. The ghoul died, still choking from the fiery cloud. Inside the cloud of smoke and fire, a commotion could be heard, but the dense, choking smoke made it impossible to see what was going on.
Confined in the hallways, the smoke drifted out to cover those standing nearby, as well. Your eyes burned from the acrid smoke, and your throat and lungs tickled. Everyone began to cough at the irritation.
Here is the map
The light patch in the hallway represents the smoke cloud.