Here's the whole story:
I took the kids out for a walk for about an hour. As we approached our apartment, the teen-age girl who lives downstairs ran up to me, saying something that I did not understand. When I told her I didn't understand, she said (in Russian), "Water is dripping!"
Water is dripping? This cannot be good.
The kids and I started to rush home, when my new friend Marina walked up. "I was going to call you, but instead I just decided to come find you," she said. I consider her appearance a miracle. She had never just decided to come find me without calling before, and hasn't since. But God knew I needed her at that moment.
"Oh, Marina," I said. "Water is dripping!"
"Water is dripping! Want me to come with you?"
"Yes!"
So, home we all went.
Within minutes after I opened our front door, two very large men rushed in and started playing with our radiator. I didn't see much water -- just some drops on the floor and the kitchen table, which is a good eight feet away from the radiator.
Turns out, that's because all the water sank down to our neighbors' kitchen. The kitchen they had just finished remodeling. When their ceiling started dripping, the neighbors called the zhek (kind of like the building managers, but more governmental), and the zhek turned off the water, but they were eager to turn it back on, and they needed to fix our radiator first.
They kept asking me questions, like, "When did you install this radiator?" (We didn't, the landlord did more than four years ago.) I suspected they didn't believe me when they referred to one part of the mechanism as "American."
They left saying vague, unsettling things like, "We tried to fix it." In retrospect, I think that's because they're afraid they will have to pay for the damage -- kind of like how you're never supposed to admit fault after an auto accident.
As all this was going on at our apartment, Eric was at work. The lady who answers the phones walked up to him and said, "Do you know anyone who lives at 44 Trostyanetskaya (not our address -- but close), on the fourth floor (not our floor -- but close), with two boys named Dietrich and Lev (yep, we know those boys)?"
Turns out, as her daughter was searching for me, our neighbor had somehow figured out where Eric works, learned our children's names, found the phone number and was calling him.
Soon after the zhek men left, Eric showed up. He stopped by the neighbors' to check out the damage, but there wasn't much he could do, so he went back to the seminary to pick up the guest we were expecting for dinner that night. Because, of course, if you're going to have a crisis in your kitchen, you're also going to be expecting a guest! (Thankfully, this was a former-missionary guest who had flooded his neighbors, too. Actually, I've found most people here have a flood story. Except Marina, so I joke that I'm more Ukrainian than she is now.)
Marina offered to leave, but I asked her to please stay until Eric came back. Sure enough, a few minutes later, our neighbor came in to look at the radiator himself. He understandably did not trust that the zhek had properly fixed it, so he wanted us to call the zhek and ask them to have someone on hand when they turned the water back on, in case the problem reoccurred. Marina made that phone call for me, and they assured her that there wouldn't be a further problem.
"But you might not want to leave the house tonight," she said.
So, what happened? We don't fully know, but every year, a few days before the government turns on the heat, it runs water through the radiators. The water rushes in pretty powerfully -- you can hear it filling up the pipes. Evidently, this year, the force was just enough to loosen a bolt that hadn't been properly secured when the radiator was installed years ago.
Later that night, we got another visit from the guy on the first floor who knows everything. I don't know how else to describe him. He knows everyone, he's lived in the building forever, he's the go-to guy for problems, he knows how to fix things or who to call when there are problems -- but, as I understand, this isn't an official role. He's just kind of been appointed by the community that calls Entrance 1 home.
He checked out our damage, our downstairs neighbors' damage, and even the apartment below them (thankfully, the water didn't make it that far). And he told us all to wait and see how it dries.
Well, this is how ours dried.

Every section of our kitchen floor between the table and the radiator eventually formed a little hill like this. To make it safe to walk, we've had to pop out slats, then tape over the holes.
We had practice with this over the summer, when the high humidity caused two of the six sections to warp. Those two sections even re-warped, so they now are missing two slats each. At this point, we are floor-taping specialists.

In February, we plan to be at a conference for about a week, during which time, we will be getting a new kitchen floor. And, at some point, our poor neighbors will be getting a new ceiling.