breaking down some of the short trees and bushes to form a passage was a noisy business and tal was concerned that he would be heard in his pursuit , but the man in front was too absorbed with picking his own path through the encroaching trees and did not once turn around , obviously oblivious to the fact that he was being followed : neither once did he stop or perceptibly slow down : either his knowledge of his woodland environment was intimate or he was walking blindly , with no particular end goal in mind .