I think it's likely the copilot was exaggerating the effect on his career of the hard landing in Raeford. Combine that with some personality disorder or even mental illness and I can see making the suicide decision. Some people just can't stand not being perfect. Think of the NASA Astronaut who put on the diaper and drove TX to FL to attack her romantic rival. Or as someone else speculated he could have had illicit drugs in his blood that he knew would be detected. That probably would end his career.

Here's the Flying Magazine story on the NTSB preliminary:

https://www.flyingmag.com/ntsb-preli...air-departure/