While you are right that these roles are EVA capable - they do not or rather should not be EVA alone. Normally they have security guards armed with rifles or carbines to protect them.
Your argument with the flash is also very weak. Sure they got some kind of training but training someone to point a flasher at someone's face is very different from proper (and continued) firearm training with tools that are very deadly if not handled correctly. Your argument stems down the fact that antagonists exist, something that just, canonically almost never happens, due to our premise. I dont think I can find a single chief physician with firearm training, except in a military position maybe, which does not apply for us. Thus, the fact that an engineer or doctor (even if they are the heads) do not need guns lying in their offices.
Your are entirely right. All these roles have far more dangerous tools at their disposal. Thing is, they now also get a free pistol added to that, too. Implying that an RD would NOT make a combat rig just because he has a pistol in his office now is silly and you know that they will.
I am not convinced. What is the reasoning behind the idea of this PR anyway? There are enough guns on station. If you want one, it's easy to get one. Who asked for this?