Hi,
Leaving a company when having turmoils is not a good sign of growth. Normally there will be an adrenalin surge, fight or flight ideation when under such stress situations.
As I see come across the situation via your mail, the possible thing might be the person might have done a couple of mistakes in his work that may be due due to lack of knowledge and/or overconfidence.
This person should have accepted that he knows a very little about payroll before accepting the task and asked for help from others. The company could have done a succession planning or atleast a two or three day induction about payroll process from the employee who is leaving, when the position is handed over to other person.
Per this situation, the other employees would have complained about the salary, for salary is a very very sensitive matter, which can shatter the employee relationship with the company, thats why the COO would have got pissed and asked him to leave, which is normal scenario.
SOLUTION: A person who is having a good rapport with immediate boss can explain about his past history of quality work in other tasks of the department and give him two months time to monitor his quality.
The payroll process can be handled by some other person.
In this mean time, this person can concentrate more do a quality job, able to satisfy the company's requirement and when the situation cools down he can quit the job and look out for other opportunity.
Why I am saying this is Every part of your mistake in work is being accounted in some way and monitored by one person or other, be it employee, office boy, boss, supervisor. This will become a history in his career, ONE CANNOT LET HIMSELF/HERSELF TO BE FIRED AT ANY SITUATION DUE TO MISTAKES. NEVER EVER GIVE UP. . . .
Regards,
LN Battacharya