RinoZ
That's about.... a 27 meter sized cube worth of acid there? Or to put it another way...the standard volume of an Olympic size swimming pool is about 2.5 million liters so have fun swimming in 8 swimming pools worth of flesh burning, bone melting, Mana eating acids I guess. I don't doubt that the Legion must have some sort of mitigation methods but hell... caught unprepared with this kind of surprise? kinda feels bad man
I wonder. Why aren't they making mechanical trap to crash the tunnels? Or drop the roof? There is multiple mentions how they fight with magic to keep things in place or crash em, but just as with the acid here. Dig upwards in your chosen position, put some hatches there to prevent stuff from falling and fill it with dirt or mud. Open when needed to fully block the tunnel and/or to try to crush the tin cans. Although I do not believe that it will kill any legionnaires but at least they need to dig up the buried people. And reopen the tunnel to proceed.