Something has been puzzling me about the Praetorian battle servitors recently. They are the caterpillar-tracked, armoured and heavily armed elite of the Adeptus Mechanicus ground troops, second only to the dwindling robot cohorts. They are highly respected and revered.

However, this goes completely at odds with being described as "servitors" in some background. By it's very name a servitor is build to serve, it is a bionic slave. The servitors serving the Adeptus Mechanics in their billions are a slave workforce, subservient to the Tech Priests.

So, how do these terms fit together? Praetorians are therefore the elite of the elite, carrying experimental weapons even other Tech Priests do not get the honour to test, yet if they are servitors that essentially makes them lobotmised toy soldiers, and the fact that these creatures are used as the testbed for experimental weapons means it's not a loss if one is accidentally turned into a steaming pile of molten slag.

In the Deux Ex Mechanicus short story that describes a Necron leader of some kind (most likely the Deciever). In the story the Praetorians seem to be reprogrammed more like machines than humans, so they fit more into the armoured battle servitor niche here.

I simply don't understand how the most powerful and elite fighting force of the Adeptus Mechanicus "footsoldiers" are expected to be effective with half their brains drilled out...? In my mind they are a few steps up from the gun servitors that are sometimes seen on the 40k battlefield, they are not treated as followers of an individual such as an Inquisitor, I believe they form their own fighting units.

I'm asking to see what other people's intepretations are, whether they are just servitors with more blades, more guns and spinny gubbinz instead of legs, or whether they have sentience/authority of their own?