From where Ahnasha was hiding, Sabine should have been able to see her at the moment. It was important that Sabine know where she was from the beginning, as she would have to remain particularly perceptive in order to keep track of Ahnasha through her infiltration. She was going to be invisible as she went into camp, so the enemy and Sabine alike would not be able to see her directly. To know where Ahnasha was, Sabine would have to pay attention to how she affected her surroundings as she moved, which would at least be possible since Sabine knew roughly where to look. If, at any point, Sabine lost track of Ahnasha, it would be much harder for her to give precise directions as she infiltrated the camp. Several of the signals they had devised involved a direction from Ahnasha's perspective. 

As soon as Ahnasha received Sabine's signal, she paused a moment, did her best to keep her mind clear and focused, and cast the invisibility spell upon herself. Her steps towards the camp were light and deliberate, her presence almost imperceptible to one who did not know exactly where to look. Even Sabine would have to use some educated guesses to approximately guess her location. 

In the camp, Sabine would be able to see that the Orc currently had his eye on the east side of camp, rather than the south with Ahnasha. The Breton Zealot had also emerged from one of the tents and had stopped Do'rhajul, apparently for a conversation. Otherwise, there was not any activity of note. Thusfar, their enemy did not seem to suspect anything was wrong.