the Captain initiated the “Rapid Disembarkation” procedure which is an SOP in Aer Lingus which is, in effect, a halfway step between a full evacuation and normal disembarkation.
As suggested in the other posts, passengers have only been briefed in two kinds of exit procedures: Normal (take your time and your bags) and Emergency (find the nearest exit, and leave everything non human behind). It is not reasonable to expect passengers to distinguish something halfway in between, so in fairness to the pax, particularly those seated in the exit row who have been told to open the overwing exits in case of emergency, one can hardly blame them for assuming the worst once prompted by an ambiguous announcement.
If the airline procedures allow for something in between, that should be properly explained to the pax in advance, and if the overwing exits are not to be used, that should be briefed to the exit row pax as well.