She has the sick sensation of being sure she's made a mistake and also sure it's too late to fix it. Well, she's probably committed to dying on her feet, at this point, she doesn't think she can pass running away off as a good faith attempt to follow orders, and anyway it's not like she had any way to know what they'd do if she stayed.
Although it's really not obvious where else she can go. Mayyyyybe she can stop and convince them that waiting for them to object to her moving toward the door was sort of like waiting for permission?
After a few more seconds she stops and turns around and deliberately doesn't get into a fighting stance.