Seriously... I think the only people that advocate the squeaking thing when a rat bites are people that have never been bitten or people who are still getting bitten... (insert appropriate smiley face here)
Rats bite defensively out of fear, usually after running away and being cornered... or they bite out of aggression, by this I mean they attack you. If your rat is running away in terror and biting when cornered, you really have to be patient and work with him or her to get over their terror and not overwhelm them.
Squeaking in submission when a rat attacks you is only going to embolden a rat to do it again. When a rat attacks you, you shout, scream and bop or swat (with love in your heart) until your rat gets that you aren't a snack or a subordinate. You are the parent or pack leader (alpha) and you never let your rats bite you... ever and never!
Our rats walk all over me, literally and figuratively... I'm a soft touch and let them get away with more than any sane rat owner should... but they NEVER bite and I've taught them not to eat wires or damage the expensive stuff... They know there are rules, and they will push their limits but when I get mad I let them know it and they understand me. Misty even stopped attacking my answering machine and orchids after a couple meaningful conversations. She still digs in the ficus tree pot, but no longer throws the dirt on the ground and back fills her holes so I'm not supposed to notice... which is good enough for me...
But back to my point... rats that bite aren't pets, they're health hazards and you have to take the steps necessary to stop it immediately, before someone gets hurt.... I do cover how to deal with an aggressive rat in my immersion thread... right up to and including 'extreme immersion', which should ONLY be used on an aggressively biting rat when normal immersion doesn't work.
Best luck.