It's definitely possible, but my issue with him heading towards Los Carrizales and on the Masca side, is that there is a clear view of settlements. Unless he has become badly injured or incapacitated on route towards a settlement. Similarly, if he heads across the road and goes up in altitude, into the mountains, the villages become more obvious.
This is why I think he descended and why when he makes his final phone call, he is coming down from the drugs and is beginning to panic as he is confused as to the reality of where he is, because it all looks the same (see image taken from Flickr of people in this area for scale). Within the Barranco Juan Lopez/Barranco Del Retamar area, he is surrounded by mountains on all sides and no villages visible.
If he attempts to gain height to see into the distance he runs the risk of hurting himself and his energy is low and he is thirsty. So his instinct may have been to continue to descend towards the sea and yet this route is extremely dangerous and he may not have been on the proper path.
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