Because the spine had already been exposed, at this point, whether it was the staff responsible for the surgery in the interrogation room, or Dong Tianyu and the others standing behind the one-way mirror, they could all clearly see that there was a palm-sized black object on the spine of the survivor.
Because that palm-sized object was exactly lodged on the spine's wing seam, if one didn't observe carefully, they might think it was just discoloration of the spine due to illness.
However, due to the report from Dong Tianyu and another person, the staff in the interrogation room immediately took photographs when they discovered this condition, and then another survivor retrieved something resembling a triple-pronged hook from somewhere.
Zachary and Yara didn't understand why, clearly being a special item similar to one for climbing over walls, it would be brought out at this moment.
