A few explanations are in order

Despite appearances, your plan came off rather well.

Drux's future prison had been prepared well in advance. Scouts had been sent out searching for a suitable site before any of the other preparations had begun. They had found a natural dip, clear of any trees, close to the hollow, but far away enough to mask your activities. The majority of the spiders had then been put to work clearing it of brush and digging it out, making it much deeper.

Then, the real work had begun. You spent a full day creating a layer of water-tight Barrier over the bottom of the entire depression. This three several purposes. First, it provided a foundation to anchor the dome you would eventually build over Drux and his army. Second, it prevented the black spiders from trying to tunnel their way out of their prison. Finally, it ensured that the Herbal Flow would not be absorbed by the ground and drain away.

The Herbal Flow was necessary to ensure your prisoners wouldn't die. If the spiders died, it would defeat the whole purpose of the trap. They would just respawn, and start attacking you all over again. As an added bonus, the pleasure inducing properties of Herbal Flow meant the spiders would exist in a constant, blissful haze, making it much harder for them to plan escape attempts.

Once you were done laying down the Barrier, Thex and his weavers set to work creating the physical trap itself. They had started by creating a dense mat of sticky web on top of the Barrier. Above that they had woven a strong sheet, meant to bear the wait of Drux's army. The sheet had been specifically designed to come apart once it was triggered, dropping those standing on it down onto the adhesive layer below. According to Thex, it was the most complex piece of weaving he had ever attempted, and it taken them several days to complete.

Once Drux's prison was prepared, you were ready to get the ball rolling. The attack on Drux's hollow was ploy, meant to draw Drux and his forces out into the open. The spiders with you were selected not only for their fighting skill, but also for their ability to follow orders. It was imperative that they disengage when told. The goal was to keep your forces intact to give your enemy something to chase. There were just enough of you to give the black spiders a convincing fight, but a prolonged engagement was out of the question.

Things almost fell apart when Drux did not take your bait. The verbal **** you directed towards the black spiders was a **** improvisation, one last attempt to stave off failure. The **** was intended to provoke the spiders, accomplishing what you **** could not. None of your anger was feigned though. You'd put everything you had into this plan. Disappointment and frustration provided ample fuel for your rage.

However, although you had deliberately intended to incite the black spiders, you were unprepared for the vehemence of their response. When they first started chasing you, you actually forgot that you were supposed to leading them into a trap. You spent several minutes simply running away, with no other objective but to escape, nor were you alone. The entire party were supposed to stay together all the way to the ambush site in order to limit the possibility of any of the black spiders getting distracted. None of you were expecting the very real panic caused by being chased.

In the end though, you remembered where you supposed to be going. You had fortunately managed not to get yourself lost, and were able to start heading in the right direction, leading Drux and his forces into your trap. Now, your enemy is defeated and contained, leaving you free to pursue whatever path you desire.