The ambulance shows up within just a couple of minutes; the car that struck her was empty and has stopped in its tracks to shelter her place on the asphalt and account for its failure to brake in time. It also called the ambulance, though so too, redundantly, did a passerby.

Does she appear to have a concussion based on diagnostics such as "shining a light into her eyes" and "asking about whether she is oriented to time place and person"?

Vivi's eyes are a little dilated with pain, on account of how something really hurts, though she can't quite figure out what hurts or why something would hurt right now. She was just trying to get to lectures! She isn't sure why she's on the ground. She wants to go to Foundations of Cryptography very badly and she is annoyed that she has, for some reason, stopped making any progress on this. And now there are people shining lights in her eyes! She vaguely attempts to bat the annoying light away. 

She is absolutely not oriented to time, place, or person. She blinks slowly at the confusing questions and says, "Want... study, try, angry, cryptography! Confusion! Want no! Go! Where?"

Okay, they think that's plausibly a concussion. (They arrived a bit too late to catch a report that she was like this before the car hit her.) She's going in the ambulance now. Can she tell them who her emergency contact is? Failing that, has she got useful identifying documents on her - ah, a driver's license, don't see too many of those these days.

Wait, why do they want her to go in an ambulance? Do they not understand that she's trying to go to her cryptography lecture? She doesn't want to miss the first one of term and then already be needing to do catch-up work before she's even got started, she'll make such a bad first impression. Vivi believes it is unladylike to kick people or punch them, but this will not stop her from vehemently wriggling against anyone attempting to physically move her into an ambulance. She doesn't do a very good job because her ribs keep sending her confusingly massive amounts of pain signal and then she feels weirdly like she can't breathe well. 

She's got a pocket full of annotated grocery receipts, a pocket full of empty Lays potato crisp packets folded into various origami shapes, and a different pocket full of index cards written in a mixture of four alphabets and several homemade cyphers, but they can eventually dig out a student card and driver's licence and a medical info card to identify her as Vivian Angus, a 20-year-old MIT study-abroad student from Ireland with severe allergies to sesame and latex. 

Good to know about the severe allergies! Wow she really needs to stop squirming like that. Is she at all responsive to instructions to cut that out from human voices if her ribs aren't doing the trick?

Instructions to cut that out get a frustrated: "Why?" 

Vivi doesn't understand why she can't string words together all of a sudden, but surely it can't be that difficult to communicate what she wants. "I want go," she produces with noticeable effort. "Want... to...." - there's a long pause while she figures out how to glue the parts of an infinitive together, there's too many parts to infinitives - "going."

"We know you want to go, but you are injured. You got hit by a car. You're badly hurt. You need the emergency room."

....and what does any of that have to do with the price of tea in China? 

"Why?" 

"A car hit you." This is clearly not working. "You're hurt. Rest. We're taking care of you."

A car hit her and therefore cryptography isn't interesting anymore? A car hit her and therefore lectures are cancelled? A car hit her so now people like her more than before and people will want to take care of her? A car hit her and caused time-travel and now it is bedtime? None of those sound right! Maybe a car hit her and that's why she's confused? She totally could have a concussion, and a concussion would be a reason not to go to lectures... but a concussion wouldn't explain why her ribs hurt. Could a car crash explain why her ribs hurt? But she wasn't driving, and besides, hurt ribs won't stop her going to lectures.... 

None of this sounds like good reasons for resting! "No," she insists, "cryptography." 

Perhaps it will help if she gestures! She points in the direction of what she is pretty sure is the way to lectures. 

"No cryptography today."

but she waited for months and months...

She is about to just leave and figure this out on her own when her ribs make a kind of ugly crunching sound that.... seems like it might be connected, somehow, to something she did. It's really unpleasant and being unable to express with words how unpleasant it is makes her want to burst out crying. But she can't quite figure out how to burst out crying so she settles for making a strangled sort of screeching noise and shouting: "Why?" 

"Vivian," maybe her name will help, it was on her ID, "Vivian, you've got broken ribs. Don't move. You'll hurt yourself worse if you move."

They also know her name? How do they know her name? Oh no is this a terribly embarrassing situation where she's totally blanking on someone who she should absolutely know?

Why is she suddenly so stupid?

...maybe there's something wrong with her? She's kind of disoriented. 

She is grudgingly willing to attempt not moving, though she still has no idea how that's going to help her make it to lectures on time, or what any of this has to do with cars. Are they going to put her in the ambulance and are they willing to let her direct the ambulance (through gestures and impatient pained grimacing) towards her lecture? 

Oh she's in the ambulance now and it's going wherever it wants which she can't tell if it's her lecture or not from the gurney.

Well, Vivi is sort of out of plans that don't involve lying on the gurney and making pain noises, and coming up with new plans is surprisingly effortful.

It's kind of fascinating how her ribs hurt, but this just doesn't seem like a very important fact about the world. Vivi is pretty sure that's normally the sort of thing that is really important. And it is mindblowingly awful, just - not in a way that seems very relevant to her life. It's like hearing about a rare deadly disease with horrifying symptoms, but then learning that it's genetic and she can't get it, so she just gets to hateread the Wikipedia articles and text pictures of weird skin lesions to her favourite pre-med friend and then go back to looking at cats. 

So if there is something wrong with her, she reasons, it's probably not her ribs. It's something to do with her being so confused. She can't figure out anything from her day today that seems relevant, but she can go through her standard checklists for when she's having a problem: has she taken her breaks today? Does she need a snack? Is she staying hydrated?

...maybe that one!

Now to communicate it through the stutter she's suddenly, frustratingly, developed out of nowhere as though her day wasn't going badly enough already.

"Apple juice?" she enunciates very clearly. She has a half jug of that left in her fridge, she's pretty sure. 

"You can ask at the hospital, if they don't need to operate they can get you apple juice."

"Hospital????"

Will they let her off the gurney please? 

Absolutely not. "You need a hospital. You're hurt."

But why does that mean she can't get off the gurney? The hospital will either have apple juice or not have apple juice, regardless of whether she gets off the gurney?

She contemplates briefly how to express this and tries, "Juice yes... Bed no."

"You need to lie down, because you are hurt."

"Hurt, yes. Lie down, why?" 

"...because you're hurt."

So all hurt people need to lie down now? What about people who are throwing up and need to not get it on themselves? What about people who are on fire and need to put it out? If she's stubbed her toe, does she need to lie down? That's ridiculous nonsense and she is tired of this situation. 

How thoroughly restrained is she and can she go leave through that nice visible door right there and go get her apple juice?