Well first off I strongly dispute that displays of arousal are non-social. Biologically they are displays to indicate availability and to attract a mate, they are social by necessity.
The last time I checked, the U.S. consensus is that the ideally sexually arousing woman has the face of a twelve-year-old girl, the breasts of a nursing mother, and the body of a boy athlete.
No-no-no,
displays of arousal are 100% social.
Arousal itself isn't. Arousal is arousal and defined biologically (and actually that's why libido is lowering with age - when you would be perfectly ridden of hormones working in arousal, oxytocin for example, you would quite probably be dead, or at least have quite serious problems). How society and person itself reacting on people showing arousal is completly another matter.
I'm sorry for bringing example, if somebody would see it as offensive, that's an example I had in university.
Let's imagine you feel arousal when see plush chairs. You feel arousal, but in the society you lives it's no-go. People demand to you to conform and feel arousal to a woman who has the face of a twelve-year-old girl, the breasts of a nursing mother, and the body of a boy athlete (let's use US Target for simplicity), but you can't and plush chairs is your thing. You're shunned as freak by people around, "that's ok to feel arousal to US Target, but plush chairs? whats wrong with you?". Hello, social rejection.
It's not the worst scenario. It's quite possible you feel arousal but voices in your own head speaks to you - "no-go". "People like you are counted as freaks around here, and we don't want this to happen with us, do we? Shush back into subconcious, this chair, let's not be aware and hit that US Target moving around!" To help this voices, humans have help button "activate arousal by stimulating erogenous zones", and also humans are rewarded with oxytocin blast for conforming society (same oxytocin that activating in sexual arousal), so person in question can live in happy marriage with US Target for years. But stress would accumulate, and quite possibly would boom sooner or later, some way or another. Hello, sexuality-based traumas.
If you had to consciously coordinate walking, you couldn't react fast enough to keep your balance.
Quite the opposite. If I really need to keep my balance (let's say it's unknown night forest) I would drop reflexive walking and start to look my steps. As conditions became less familiar, I would take more attention.
The problem with consciousness isn't that it's slow. Problem is it's small. Human consciousness have little field of attention, so untrained person can't, say, thinking about six or seven unrelated issues at once. Imagine computer with two terabyte RAM installed, but application is allowed to get 256 kB - of course it would looks slow. But if anything else you have is oversized software routines written by awful programmer and tending to be bugged as a hell and sometimes crushing your system, you'll use something beyond this 256 kBs only when you're perfectly sure in situation.
Anyway, as Bubbles declaring that he haven't access to the part of mind Corpse Witch blocked, and point it as something non-usual, it's safe to assume she normally have full access to her mind.
That is why AIs can learn arousal. They no doubt feel something different in their metal and plastic bodies than I do, but I strongly suspect that women, much younger men, and much older men do too, and that it still counts as arousal.
Actually it's called "Qualia problem" - how to prove that my sensual experience is correlated with yours in any way - and is one of the most heatenly debated questions of modern psychology.

But with arousal it's quite simpler then with, for example, color perception. Arousal have physiological markers, no markers - no arousal.
Let me try to show what I mean by this way:
Imagine situation in "Basic Decency", but there Bubbles is a human woman, not AI. What is happening?
She's entering the room and seeing Faye bottom. Faye is her thing, her body reacts with arousal, her nipples erecting, pupils dilating... well, I will not list full spectrum. Bubbles identify this reaction as arousal. AFAIK in US (and in Western World) it's not counted nice to feel arousal to another person beyond some specific situations (nobody said social demands are always reasonable or even feasible; but, for reference, recall reaction Faye had when Marten asked her can he lust her secretly, it's 4), so she feel bad and shunned, it's mixing with arousal, and her inability to hide arousal. "That's not how good girls behave!", she is lectured by her own morality. So she turns around, shunned, and asking Faye to remove stress factor. Perfectly understandable and common situation, I believe most of us being here at least once.
Ok, current situation.
Bubbles entering room and seeing Faye bottom. Some X happens. Bubbles identify this X as arousal, then every step from previous example, because it's how AIs build their social behavour (and I'm completly OK with it). X definitly isn't human arousal, so it's some reaction put into her body or mind which Bubbles identify with arousal and then behave following social protocols. What is X?
If it's some kind of uncontrollable special reaction directly placed there to mimic human arousal (for example, some kind of software subroutine that downcycling processors a bit and loading part of RAM with nasty pictures), who placed it there, and how exactly it's triggering?