Why does trying to break into the NT 3.1 kernel reboot my 486DX4 machine?

While installing Windows NT 3.1 worked perfectly, I really like to tinker with my retro stuff. The Windows NT 3.1 CD comes with the full set of debugging symbols, I'm curious into investigating why NetDDE throws an error into the event log, and the system crashes with a specific EISA ethernet card (which might be due to faulty hardware), so I decided to dive into kernel debugging. Setting up kernel debugging is straight-forward, once you realize you should use the i386kd executable supplied with Windows NT 3.1 instead of kd/ntkd from the current Windows 10 develepmont kit.

As soon as I want to break in (using Ctrl-C in i386kd), the target machine reboots instead of providing a kd> prompt.

Such an obscure question and bug, and yet, there's someone providing a detailed answer - and a fix.