Explorer Not Working after Knock on Counter

[SirHillary]

I was wearing my 14270 (~1991) when I knocked it on the edge of my kitchen's quartz countertop. I didn't think it was particularly hard, but my wife joked: "way to go, you ruined your watch." To my surprise/devastation, my watch was no longer running when I looked down. I tried to wind it, but was faced with immediate resistance, so did not try to wind it further. And now I hear and feel something loose in the case (a large object, maybe the rotor?).

The watch is insured, and I'm going to take it to a repair shop tomorrow to get an estimate, but I'm just dying inside a little bit and also wondering how a watch of this quality just completely broke after one knock. I bought the watch preowned from a reputable dealer less than a month ago (authenticity guaranty, inspected and serviced) - it has been working great since I got it, but now I'm wondering if there was some sort of defect.

Has this happened to anyone else and, if so, what was the result?