Welcome to Robotworld, Faye, where literally everything is quite likely sentient and has an attitude. I'm sure that you've made an enemy of the toilet too!
Y'know, I'm seriously thinking now that Jeph is writing this to be a slap upside Faye's head. Not only does her attitude lead her to make
enemies with all her co-workers but she eventually has to quit because of the poisonous atmosphere she's created for herself in the workplace! So, she finds that she
actually doesn't understand people at all, is very bad at making friends and is left wondering if her 'quirks' may be the cause of her having so few friends and so few options.
Basically, she only got away with it this long because Marten is (or at least used to be) an emotionally-crippled doormat and Dora is her friend and thus used to look the other way when she was mean to her employees. Maybe the time has come for her to re-assess how she interacts with people?
I know that it sounds a downer but, sometimes, you need to do that to force your characters to grow.
Why would humanoid be the best shape for a combat robot? How effective is a bipedal tank?
Highly ineffective, actually. The US Army crunched the numbers and found that battlemechs' high silhouette made them a sitting duck for anti-tank missiles and artillery. Additionally, they could be spotted and tracked by enemies from far further away.
The fact that Jeremy is there has two possible, rather disturbing implications:
1) Your average assembly arm can develop a taste for illegal violence
2) Jeremy got laid of in a way and now has to make his living by fighting.
Or that, like Faye and Bubbles, he's one of the URFL's repair and maintenance staff, no more.