At DUB T2 (and T1 is different) you do have the option of using Flight Connections to stay airside for your next flight, but the expectation is that you stay airside. Broadly speaking you will get lounge access 3 hours before the departing flight from DUB. Arriving passengers cannot access the DUB lounges unless airside, and they can only do that if using Flight Connections. So unless there are some other details here, I can't see this working at DUB. Moreover while the T1 lounge is OK (and accessible to T2 passengers) the T2 lounge is pretty unspectacular, it's just a large office with lots of chairs crammed in and a limited food and beverage range. Sometimes T1 gets full and they refer people over the T2 (which is actually only a short distance away, just to confuse everyone).