The entire sequence makes me wonder whether they were so fixated on identifying and avoiding the wires that they knew where there, that in searching for them they failed to spot them and instead inadvertently flew directly into them. Any pilot will attest to the difficulty (or even impossibility) of identifying known wires without the normal cues such as pylons or other landmark structures. In such a massive 3D space they may have been almost impossible to see, especially if you become focused on where you believe they are, rather than where they actually are. Even four sets of trained eyes is no guarantee of the outcome.