The flow is obviously towards the sidewalls, else the A/C would gag on all the spillage that is the norm for aviation catering.
Imho, the key aspect here is the flow time of the filtered air. If the air is exchanged every 90 seconds and the cabin is 13 feet in diameter, the flow rate is only about 1 foot every 7 seconds.
Add to this disturbances from the proximate passengers, traffic down the aisles and perhaps even sneezes, there is ample time to get a full dose of the virus if one comes in the vicinity of an infected passenger.
There is a separate thread here about multiple transmissions on a TUI flight, so I think it is beating a dead horse to claim that somehow there is not a problem when it has been demonstrated in real life.