A person committing suicide often changes its mind in the last moments. Anyone thought about the possibility that maybe after he locked out the captain, set the AP
to descent and waited a few moments to be sure the plane would hit ground in the next 5 minutes he took some knockout drops to seal his fate?
Even more speculation, I know. But it just crossed my mind as I was thinking about why there was zero response from the cockpit while normal breathing was heard on the CVR.
Anyway, surely this will be confirmed (or not) by forensic analysis.