I am very much aware of how the Wing 1 trash was set up, I've been playing since May 2008.
And you are wrong on "this applies to any raid": T4 trash between Imp and Zodiac stay dead for a few days (2?) as well as I believe the trash in Entity's room. In T5, the trash between Champ and Kylikki would stay dead for a quite some time, not sure on the actual time. Not sure about the other trash in T5 tbh. And in T6, the trash stays dead for very long time as well, haven't really paid attention to actual time but at least a day?