"The four lifts in the middle of the room each rumble to life as chains click and clack over their gear mechanisms. The four platforms slowly begin descending and you're able to clearly hear angry shouts and organized commands; you can also see numerous people on each lift." What do you guys do?"

The three CN characters: let's fight em! The other two: we are pretty spent from the boss fight... CN: we got it! Let's fight em! The cleric: I have a fire ball and a healing spell left. That's it. CN: it's OK! We can take em!

Me, sensing the party is about to do something dumb: "the lifts seem to jerk to a collective stop. (Insight check revealed a small malfunction) Some of the people on it swear and make remarks indicating they cant wait to spring this trap after all the misery you guys put them through"

The barb, king of tanks: I don't think I can stop all that damage. We should run." CN: nonsense! Let them come!

"The lifts begin descending again. There are clearly 6 people on each lift and all of them look fairly seasoned. Numerous casters can be seen."

CNs: Let's hide in the alcove!

Me: Totally meta: is that your final answer? You guys are going to fight a reinforced group of soldiers after exhausting many resources on a boss? Them: Yup! They won't find us! (The room they're in isn't that big and the alcove will quickly be discovered)

"The lifts hit the ground. The leader yells at the prisoners on the other side of the room and rolls intimidation to make them tell him where the PCs went. The leader easily makes the roll and tells all his guys to quickly form up around the mouth of your alcove."

There are the events immediately leading up to their situation. The feywalker uses a class ability to chase across the room towards an exit and is quickly KOed by casters. The barb and fighter take a round of combat at the mouth of the alcove, then back up as the bard uses thunder wave into the alcove entrance ceiling, causing it to collapse and obscure the entrance. End scene