The "retirement" timing here is interesting. OPM's own "apply for retirement" forms state to supply the filled out form to one's HR office at least 60 days before one's retirement date to give time for it to be processed by HR and OPM.

So either this official got the worlds fastest processing of a retirement application through their HR department and through OPM, or he was already retiring on Jan 31 anyway and the timing is just a coincidence.

It is common in federal service to retire on the last day of the month because retirement pensions are paid on the first day of each month, so one has the smallest 'gap' in payments by doing so.