The trembling from the ground made Alex more anxious.
The shrill screams weren't as far as they initially were.
According to what Al told him to do. Alex was to
Avoid the immortal plants that give out strong chaotic qi pulses or light.
And that was what was all around Alex. He didn't want to run randomly only to meet something that he wished to avoid.
But as things are, Alex knew that if he didn't leave his current position, he was likely to get caught by whatever was chasing those who were screaming.
There was also the option of turning back and leaving the Fog Garden.
But Al had mentioned before that this indeed is a labyrinth. If he chooses to leave the Fog Garden now, through the entrance he came from, he wouldn't be able to reenter the Fog Garden through that same entrance.
Using the stars in the Labyrinth, Alex would have to navigate around to search for another entrance.