You wont get sacked for walking out, you will just get a verbal warning, you can only get sacked within the probation period I think.
I am currently having a major tiffle with my boss at work, I nearly did walk out after we were shouting at each other, when I look back, I wish I did actualy as he accused me of three things that I didnt do or he was wrong about and having him **** you off really annoyed me.
Im quite worried about the people here with no spines, yes they are your manager and you should respect them, but they are not god, and if you are unhappy with procedures you should question them, if you get a smartarse one line comment back from him, ask him "why?" you wont learn if you dont ask.
I have personally never argued against procdeures before, but if they start questioning my performance at work, then I start kicking off and arguing which is always worth a shot. I find that a lot of managers bully there employees, if you stick up yourself, they leave you alone, some poor guy at work takes a lot of crap over tiny things which other people get away with, when your getting a drilling, nodding your head and say "yes sir, sorry sir" will just give them a power trip