I boarded a BD 321 as SLF around 2100. Some minutes later Captain comes on to say we're being delayed until 2240 (slot) due to "an incident on the airfield". The delay failed to materialise and we pushed back about 10 minutes later. Incidently, we had a nice late Go-Around on approach to rwy 10 (DUB) due to "ATC decided to line another Aircraft up".