If you're entering the tunnel from the grove, then you only really need to disable the first statue before killing the goblins, which is easy enough just by ...
sneaking a character up to the first rune on the left. The other statues can be disabled after the fight, using the other two? three? runes. You might need to play around with the order in which you go around the caves in order to avoid getting blasted, or sneak to them to avoid being detected by the glowing eyes.
You certainly also used to be able to destroy the statues, though I've not tried in this release. I'm guessing they're resistant or immune to certain damage types, or have the property that means they only get damaged if the total damage is over 10. Right clicking and examining should show what they're protected against and so help decide what might work better, if you're determined to go that route!
