Adam wanted more powerful goblin beasts or more numerous goblin beast guards to be sent out to the forest outside of the goblin city to search for the enemy or to increase security.
Them doing so would allow him to gauge more about the goblin beasts that he was facing and would allow him to pick off more of the goblin beasts without needing to go into the goblin beast city that would be densely populated with powerful goblin beasts.
After taking down nearly 50 goblin beasts guards around the forest that was around the goblin beast city, Adam opted to place the bodies of the goblin beasts that he killed along the edges of the floor.
Carrying them all back to that small plot of land that used to be a safe zone was too time consuming and there wasn't much space anyway, so placing them around the edges would be more efficient.