Title translation: Only the Stars of Heaven Know Where Pae is.
When Steve is jackhammering the concrete the others stop him because they see part of the clothes of the deceased. Following that they are chiseling by hand and you can clearly see there's no damage to the corpse. As anyone that has drilled a hole with a hand drill there's no way you know when the bit comes out the other side, just like no one can predict when the cement ends and body begins, especially with a very heavy jackhammer.