Sentry Drones have very little combat ability, but they're not really meant for combat. They are deployed into the field, typically in mazelike areas with low visibility, to watch out for invading Autobots. Once they spot an intruder, they launch a flare high into the sky, signalling nearby Decepticlone units to come in and take care of the problem, usually in the form of a Dropship. Once this has been done, they will fly off in order to alert any nearby Decepticlone patrols. As such, Sentry Drones are best taken out from afar, or with a surprise attack at close-range; firing on a Sentry Drone and missing will still cause it to launch its signal flare. Sentry Drones remain static, though only for a few seconds, as they prepare to fire their flare; they can still be taken out during this time.
Sentry Drones tend to run once they've released their signal flare. If cornered, they have a light laser blaster to keep their pursuers occupied. They cannot fly at high altitudes, so their escape options are fairly limited.