The grunting sound that the sentinel made each time he landed on top of Vandread was something that Vandread continued to hear even after the sentinel had stopped jumping on him. Vandread could tell because he was constantly rolling around quickly on the ground to avoid the sentinel's attacks.
The sentinel's footfall would destroy the ground it had been standing on, leaving behind a gaping hole. Because Vandread had seen firsthand how even a small movement could result in a significant amount of damage, he knew that he could not risk letting the sentinel strike him in the face without taking precautions.
For if that much of the sentinel's weight had even landed on him, he would have been instantly crushed to death the moment it happened. It was insane to believe that the sentinel could move so quickly despite the fact that each of his jumps carried such a significant amount of weight.
