Commander Cody uses a night vision device attached to his helmet. Upon activation, a red light turns on at the front. Night vision devices do not visibly glow at the front because they would thus give away the position of their wearer.
When Obi-Wan, Anakin, and the clone troopers are attempting to track Luminara through the catacombs, at one point they must squat to pass through a narrow passage. Obi-Wan offers to go first, using his lightsaber for illumination. Given the extremely short ceiling and the manner in which he was holding the lightsaber, the lightsaber should have sliced through the ceiling.
Despite the Star Wars universe's predilection for metric measurement, Obi-Wan Kenobi uses "miles" in describing the extent of the Geonosian catacombs.