Shut off while in R, engine cranks but will not start?

Have no power to door locks, dome lights or the OBDII port.

It did restart twice, but second time it died while trying to use voltmeter meter to check alternator. Car was running with lights (inside and out), radio, blinker, A/C, defroster was going.

Battery reads 12.57
Alternator was 14.1/14.3 (when it started)

Fuses and relays seem to be okay.

I just don't understand why some of the electrical components are not getting power, but the dash lights come on like normal when I try to start it.