Three days is considered the minimum to be symptomatic. It's possible, of course -- maybe very high activity accelerated the timeline -- but he spends his days

Three days is considered the minimum to be symptomatic. It's possible, of course -- maybe very high activity accelerated the timeline -- but he spends his days around hundreds of people, and then occasionally tens of thousands of people. Just walking out of the tunnel he is under the respiratory cloud of hundreds of people. It seems deeply improbable that this event was the cause, not least because the timeline isn't among the probable set.