[jvanderbot]

Yes, and for that metronome to continue "ticking" according to the normal laws of physics the distance must shrink to accommodate the limits on speed - Length contraction.

But, all the observable effects are the same under my "life raft" mental model: To an outside observer their time has stopped, to an inside observer it has not (I'm just thinking slowly). And the laws of physics are unchanged - as a function of time e.g., the number of clockwork steps per metronome tick.

I realized that my thought experiment is not special or unique. Here's the "light clock" version

https://www.emc2-explained.info/The-Light-Clock/