Fast Engineering is the second upgrade of the first path for the Monkey Engineer, costing $300 on Easy, $350 on Medium, $380 on Hard, and $430 on Impoppable. It increases the build speed of Sentry Guns from one every 10 seconds to one every 6 seconds, allowing up to 5 active sentries per engineer.
If NinjaKiwi goes offline, the maintenance screen will display a modified version of the BMC art for this upgrade, with the sentry gun being replaced with a faulty television.