The wire appears to be set up purely for tripping, there is no triggering mechanism of any sort connected to it - an extremely basic trap but cannily set. The wire is cut and the area checked for tracks. The experienced woodsman of the party check the area for tracks, the rangers by conventional means and the shaggy Artos once more getting down low and sniffing about. There is clear evidence of a small humanoid having moved around the area, apparently the trap setter. However, there is no sign of where the tracks came from or disappeared to, they are seemingly without source.
[Unless there is anything else the party wishes to do at the trapsite I am assuming you travel on]
Careful navigation of the gorge brings the party once again to the site of your makeshift camp where you encountered the Phantom.