Theorycrafting - Dvergr Protected Farm | "Is there a way to damage a dvergr ward without making them aggressive?"

So, there's a nice little Dvergr base with TONS of guys in it. I've left them alone, as I already have extractors. But then it donned on me: This would be a great place for a Jotun Puff farm!

The only problem is the Dvergr ward. If I break it myself, the Dvergr will be angry forever. If I try to lead enemies in and get it broken that way, then a lot of the Dvergr will inevitably die, making the effort pointless. Is there a way to indirectly damage structures?

Only thing I can think of off the top of my head is a felled tree log. Not sure if it's viable to try to shove a felled tree log in there... I tried a pufferfish, but seems they only deal poison damage and don't damage structures...

Any ideas?