I had a serpentine belt break and it sounds very much like what the OP described. Lost my power steering and had a heck of a time getting parked.
Just to be clear, I’m a computer nerd; my dad’s the car nerd 
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Also, my sample space is biased. These engines were often already being driven nearly to the point of explosion. So an already destructive event was more catastrophic than it could have been.
That said, almost anything could happen. You could hear a clunk and notice a moderate loss of power, with your check engine light coming on, but not much more than that. Or you could have a total loss of most fluids and all power, along with some loud and concerning things happening under the hood.
I don’t think you actually threw a rod, but you asked for fun, and the Blues Brothers is fun. The mechanic’s diagnosis so far seems reasonable but I’m not an expert.
Had the same happen to me, but I was 40 miles from home, at the airport, in a snow storm. The wise thing to do would have been to take the bus from the airport, or call AAA, but I’d already gone 5000 miles that day, and I wasn’t going to let a battery light stop me from going the last 40.
It actually was the alternator, not the serpentine belt, so the only issue was rationing power to make it home. The battery ran the wipers, blower motor, and everything necessary to make the engine go. I waited to turn the lights on until the last possible minute, but probably still drove 15 miles with the lights on.
I don’t remember if that was the first or second time I got the alternator rebuilt, but eventually they did it with the high output components, and it stopped dying annually after that.
Take this opportunity to upgrade to a hyperencabulator. It’s a key ruminant in the advancement of retrograde phenomenology.
We have an official report from the mechanic. His initial impression turns out to be correct. The water pump failed, which broke the serpentine belt, and that whipped around and broke the crankshaft sensor and its wire. It’ll be about $1800 and he’ll have it fixed in a couple days (note this doesn’t mean he will spent two days working on it, as I dropped the car at his shop without scheduling a job and we don’t know how busy he was going to be). No thrown rod. No broken timing chain or belt. No transfer case problems, or head gasket. Didn’t suck up a flock of birds, and the encabulator is fine.
A story like this one: my co-worker and our boss did a miserable one day business trip together, involving six flights. I lived closest to the airport so we met at my house and carpooled in my co-worker’s car. On the ride home, his alternator failed, and we limped home on battery power, the headlights growing dimmer and dimmer as evening fell. We pulled into my driveway and his engine finally died.
So, our boss jumped out of the car, saying “oh my look at the time!”, jumped into his own car and took off as quickly as he could.
In his haste, he cut the corner too closely around the end of a low retaining wall, and put a long gash in the passenger side of his car.
The retaining wall made out OK, though.
Very occasionally, karma is on speed dial. I love it when that happens.
That, at least, is good news. A car that won’t encabulate is no fun.
That seems awfully expensive for basically a new water pump. The rest of the stuff sounds pretty minor. But IANAM.
Around here independent shops charge $150/hr for the basic labor.
Depending on how much needs to be disassembled first to get to the water pump this could easily be a 6 book-hour job. Plus an extra hour for the sensor & wiring. So 7*150 = 1050 in labor.
Then there’s parts and shop fees.
This has got to be the nerdiest joke in the world.
And I was so proud of my Never trust an atom / They make up everything tee-shirt.
That may be. I wasn’t trying to suggest that the mechanic was overcharging, I was just surprised. I’d hate to get a $1800 repair bill!
When I had my alternator replaced, which superficially sounds sorta kinda similar, the cost was $551 (plus tax). But maybe a water pump is more complicated, plus the other stuff.
The harmonic stabilizer?
Video on how to do it is right here.
A water pump is usually more involved. You first need to drain the coolant from the radiator, and the removal of the pump is probably going to make a bit of a mess (with coolant going here and there). The old gasket material needs to be removed, and all surfaces need to be cleaned. After the pump is installed, coolant needs to be added, followed by a procedure to remove air in the system. And then you hope there are no leaks. It takes time, a few gallon of new coolant, and the old coolant needs to be properly disposed of.
Oh, and why is it called a water pump? Why isn’t it called a coolant pump? Always wondered about that.
Because when you had a Ford Model T, you probably did put water in it, at least in summer. And if the water boiled off, why, you’d just go over to farmer MacDonald and ask for a bucket of well-water! 
We have the car back and it runs fine. Interestingly, it was noisy before all this misadventure, for years. It had an engine sound kind of like some heavy sheet metal structure was rubbing on some rotating part, like a shield that was touching the edge of a pulley. There was a little debate as to whether this was an unusual sound for a car to make, or not. Now, this sound has gone away.
I wonder if water pumps can fail slowly and make such a sound.
I also wonder if there actually was some sheet metal rubbing a pulley, and it got fixed during this repair (whether intentionally or inadvertently).
This seems to be good thread to semi-hijack.
On Monday (Memorial Day) I drove ~15 miles to a nearby state park with my 2016 Toyota Prius without incident.
After hiking I started the car – all sorts of warnings went off – mostly “Hybrid System Malfunction” and “Pre-Collision System Malfunction”. On the drive home (the still RAN) I saw “Lane Departure Malfunction” and ONCE “Brake System Low”
I called the dealership at 7:05 AM Tuesday and the earliest they could schedule me was June 11, but later they said drop it off and they will try to squeeze it in.
While they finally called today (Thursday) and said they THINK it is the hybrid system (inverter) water pump. They need to check some more stuff. If it IS the water pump the car isn’t good to drive and it will be next week before it is fixed.
Note that the inverter coolant pump is different than the engine coolant pump.
I guess the good news is since I am unemployed I don’t need the car so much. I have board game night tonight but have a ride, and I can bike to the local grocery store to at least get some food (not where I usually shop as it is on the small side, but it will do for a few days)
Brian
This would also make a pretty good mini-rant.
One thing your post puts into stark focus is that substantially all my own knowledge and experience as a former gearhead and semi-pro auto restorer / mechanic is useless in the face of hybrids and EVs.
It’s not that much better as to modern heavily computerized ICEs, but the difference is stark. As in “I would not know where to begin.”
Pretty much Roadside Assistance, rental car agencies, and hotels on speed dial with my EV. Haven’t needed anything in 15k miles except a windshiekd replacement (stone chip grew to a full-on crack overnight) and a slow leak/screw plugged at free service.
This the first issue that has happened to my car in almost 9 years and ~80,000 miles.
(The low mileage is partly due to Covid and partly due to my previous workplace being 4.6 miles away — I bicycled there fairly often). I have driven to Glacier and to Colorado and Arkansas from SE Minnesota.
Brian