Huh, I thought switching two things would be easier, given that Algard did it for the tower. But the position of a thing and the identity are significantly different.
Orks are complex creatures. On the one hand, it's really neat to have something to fight over. Make the fight come to you! On the other hand, having fight everywhere is also really nice.
Any given Orks position is liable to switch often whenever new information presents itself, like what the boss tells them or what another Ork thinks (so they can think the opposite and have a fight about it*).
More seriously, Orks are capable of building and using infrastructure. And while they like fighting other things, there's always fight at home.
*Sometimes, both Orks switch simultaneously, so they end up with the same opinion afterwards. And then switch again. And again. And so on. This is called an Orkscillation**.
**I want everyone to know how extremely, unreasonably pleased I am with that pun. I will ride that high for the rest of the day.
Honestly, you might be underestimating them there. Not sure the end of the world would stop the Orks from fighting.