I think Doc Savage and kaka are both right.

In the event that a restated boarding time or an annoucement has been made, stay at lounge (kaka)

If not, go to gate (Doc Savage)

A complication with So Man-Fung was that there was no gate when he entered the lounge. I suppose he should've checked the boards about 20-odd minutes before departure time (assuming he's not using an IOS device where this information may be pushed), but yesterday was such an abnormal day where delays were taking forever one doesn't expect one suddenly has to run.