Car can start even in gear! What's going on?

I *just* got this new-ro -me 75 Dart home, and it stalled when backing it off the hauler. Without thinking I turned the key again and it fired up, even while still in reverse. What's missing?

It's surely a used track car, 75, 360/727, 3.91 Sure Grip.

The guy I bought it from said he replaced the old ignition with an MSI (I think). Anyway, any thoughts? I did Google it, bit the first few pages are all things like how to start a manual in gear, how automatics cannot be started in gear...all that.