Ha, well… it's still not 100% clear to me. 
***
Did you see the first Last Jedi deleted scene?
Of course, as Phangirl, I'll have to over analyse it! 
Ok, so… Stormstroopers as indoctrinated from birth, trained by Captain Cardinal first and then Phasma. But they're immediately pushed to not only respect, but also fear Phasma. When Phasma says "who would believe a story like that." the only answer can be: not one of her troops. So the fact that they start to hesitate at the words of a known traitor that very second… clashes.
Then Phasma excecutes them all out of precaution. Thát is like her. She does the same thing in both the novel and comic, making sure no loose threads are left. Awesome! And then she loses her hand. Are you even kidding? Does she have to be a punch back for jokes about everything? I'm surprised she didn't die screaming: "I hate sand!"
But she gives a surprised grunt and then bites it back immediately, continuing the fight. Again: awesome. She's been beaten to a pulp before, a loss of limb shouldn't faze her.
And is then blown backward once more. Lets just say I like parts of it. At least I'm glad we got to see it!