Uncreatively, and shamelessly, copying this because it's basically exactly what I'd do anyways, just worded more eloquently than I have time for. I like my high perception rolls.
Mudball uses Perception to see the activities of the ruffians and maneuver around their movements, ducking when they turn and running across when they're facing away, as he gets closer to the building.
Perception: 1d20 + 8 ⇒ (5) + 8 = 13 Oops.