The Maintenance Bot is a TriOptimum robot built for performing maintenance tasks, and is equipped with a variety of tools for the many jobs it might encounter. They are both highly resilient and capable of serving in dangerous conditions. Unfortunately, Xerxes has seen fit to alter their programming, and their tools have now been turned into weapons. The first Maintenance Bot you'll see serves as the "boss" at the end of MedSci, and you'll see a few more of them in Engineering before they're replaced by more dangerous variants.
Note that there are two additional varieties of Maintenance Bot, the Security Bot and Military Bot. Please view their respective pages for more details.
Medium Hit Points, medium damage, medium attack speed, low movement speed
Armor-Piercing Bullets, EMP damage
Nanites, Portable Battery
Maintenance Bots serve as the first truly difficult enemy you'll come across, though that's mostly due to the scarcity of ammo in the early stages of the game. Maintenance Bots attack with a medium-speed energy discharge, which can be dodged even at low Agility levels, though it does enough damage to become dangerous if the Bot isn't dealt with quickly. The biggest advantage you have over the Maintenance Bot is speed: they're extremely slow-moving, so use that to your advantage, popping in and out of cover to fire some Armor-Piercing Bullets or an EMP burst. Using melee weapons and standard ammo isn't recommended, due to their low effectiveness.