I'm more bothered by the fact that nobody got nausea, or floated up a bit, or otherwise reacted when they shut down the engine and were in Zero G, than the fact that few people sat down or leaned. The woman sat down, then the gravity went away but she didn't feel like moving in that moment. Big deal. She could have looked around as it surely must feel weird, as her senses got confused where up was, but then, maybe she didn't usually feel too well after doing so, so she chose to remain still or not turn her head. I have only ever been in free fall for a couple of seconds, but those were some very confusing couple of seconds, which I suspect every transition must feel something like this. Like wondering how the horizon could be literally under me, then how the sense of ‘under’ started moving but the horizon didn't. Your intuitive reaction is not to make sudden moves, or move at all, although you do feel an urge to move your head slightly to experiment with the feeling. Given how much I love sitting on a couch the wrong way around (sitting on the backrest), sitting down during enteringzero G would probably be next favourite thing. But why she didn't feel slightly confused at to what her posture needed to be, or why parts of her didn't hover slightly, that I can't tell.
I'm also not totally convinced that gravity boots are impractical in a fictional world like the one of the show, where ground can appear and disappear at will. If you're on the free floating ISS, sure, they wouldn't be of any help, as ‘walking’ would be more cumbersome than floating around. However, to the best of my knowledge, we have never actually tried walking with mag boots in zero G, so we don't know the real limits of their usefulness. Walking with them might be less difficult than it would seem (especially if the boots assist by changing the strength of the magnet). In the show's universe, I would totally buy that someone mandated magnetic boots as safety precaution for the ever-changing acceleration – to be used for regular walking only, with floating still the preferred for zero G. But then people started walking with them, first to mess around, then out of habit – kind of how you use the touchpad of your laptop when your mouse is a foot away, even though the touchpad is ridiculously impractical device. So it became a trend, and the mag boots became a thing.