Sensing this, Chu Nan's mind immediately shook.
The reason why he returned to this secret base that he had followed Dr. Querzaros to discover was actually to find this teleportation door that should exist.
In the conversation between Dr. Querzaros and Director Romon, they had mentioned retreating a few times. Moreover, there was indeed no one in the underground base now, so they had clearly retreated.
However, the place they were at previously was the 40th floor of the Endless Abyss. The so-called retreat should naturally not only be targeted at the 40th floor. The direction they could retreat in could only be the deeper location in the Endless Abyss… the 41st floor.
Now that they could sense the existence of this teleportation door, it meant that as Chu Nan had expected, they had only destroyed the teleportation door to the 39th floor but not the 41st floor.