Raids don't end until you last the specified amount of time within the area of the raid. That's why I usually wait until the raid ends to kill stuff unless I'm trying to collect their drops. Just kite stuff around until the raid ends, then you can lead them away or kill them in small groups.

Nothing is gonna be moving around until you get back in range to load them in. If they didn't destroy your workbench before you died anything in range should still be there when you get back.