When the machine slides forward, it leaves behind an unsupported ceiling of rock. This ceiling stays briefly suspended. Then, boom! ​ — it crashes down with a bone - jarring thud.
Masina edasi nihkudes jääb maha toestamata kivimassiivist lagi, mis veidi aega vastu peab, siis aga kostub kõmin ja lagi vajub verd tarretama paneva mürtsatusega kokku.