Grammatic
Knight of Nevermore
By technicality they are correct. It is vaguely possible to be able to do multiple fields, but specializing in one is by far the most common, and usually the only, path forward many have. Especially in Imperial society during the 30k setting, you are committed to a path that best suits the Imperium's needs, and the luxury of exploring multiple paths is usually limited to only the utmost high in society.Learning the secrets of the machine to the point of being a magos is like learning an ancient craft not college every secret is closely guarded by the teacher
Also as a magos your loyalty would be to the mechanicum of Mars you would lead the skitarri forces into war not be under the command of the imperial guard
Also, I did miss it the first time so for that I apologize, but the Mechanicum would not be the ones that primarily train Psykers. The Imperium as a whole still oversees and trains psykers as needed across their worlds, and the Mechanicum of the period are more driven towards technological ends. Most of the mutants in their use, the Navis Nobilite and the Astropaths, have been granted as boons by the Emperor to bring the Mechanicum into the fold. Both such organizations are still mostly self driven and give their service to the Mechanicum after they themselves have been trained by their organizations.
This is true enough to an extent at the time, the Mechanicum is part of the Imperium but it has its own command structure, leadership and tenets that it must follow. Cross over is rare.The mechanicum at this point is its own independent empire they would not teach her she is lesser than a mere fleshling
CommanderNecro