Need (yet another) escape plan for the party in Thisteltop (spoilers)

[Gandal]

I hadn't plan it, the party got to Nettlewood,failed stealth rolls, fought all of the goblins and Gogmurth, which fled.
The alarm raised, the goblins of Thistletop prepared an ambush since the party lost time exploring the wood in search for more enemy and examining the rope bridge.
The party is:
Lvl 3 f tiefling rogue
Lvl 3 m human barbarian
Lvl 3 f aasimar garuda-blood druid
Lvl 3 m human cavalier

Once entered the building the party was lured toward the throne room and surrounded by Ripnugget + Stickfoot,Bruthazmus and about 10 goblins riding goblin dogs.
Here i did enemy stealth opposed to party perception but none of the PC spotted/heard a thing ; long story short the PCs went down one after another, the barbarian and druid sent Ripnugget and Stickfoot down but it did them no good, and since they foolishly ran into a trap i allowed the party to be defeated but asked them if they preferred change PCs or keep these.....which resulted it the chars being stripped naked,tied up and brought before Nualia.

Of course i don't want to simply kill them under torture,but neither to let them escape right away after having recovered their stuff because someone forgot it in some unguarded room.

The rogue with a very good bluff convinced Nualia to let her go in exchange for another prisoner more suitable to their captors, and Bruthazmus asked to have Shalelu to play with, so Nualia out of amusement allowed for the exchange keeping the other PCs hostages.

More, the druid companion, a tiger, fled the battle at her master command and went back to Sandpoint, s i think by the time the rogue is back in town Shalelu knows something is wrong, but the rogue has to lure her into a trap to "save" the rest (but none trusts Nualia).

So now i'm a bit lost ; where and for how long to keep the other three PCs and how to make them escape ?(i think Orik may have a part in this,he isn't utterly evil after all) How to play Shalelu ? I know she won't let the enemy at Thistletop take her, but she doesn't want to let the PCs die if she can avoid it.

Any good suggestion please?

[Kalshane]

Shalelu isn't going to lay down for her life for some people she just met (which she would be doing if Bruthazmus got a hold of her), Heroes of Sandpoint or no.

Is the Rogue truly planning on betraying Shalelu? If not, she could probably get Shalelu, Ameiko and perhaps some other ex-adventurer NPCs that have favorable opinions of the party (if there are any) to put together a rescue plan.

Orik is another out. He could offer to release the PCs if they agree to help him get Lyrie out of there (not that she's likely to go willingly) or even just get him out of there. In my game a played him very much as a hired sword that found himself over his head among some very scary people but with no obvious options to extract himself without ending up dead. A party of adventurers present a perfect opportunity.

[Gandal]

The rogue said she isn't really going to betray Shalelu but they also have to approach Thistletop again well in sight, un-armed and un-armored,so Shalelu isn't happy of the situation too.

She isn't going to walk in there without weapons and armor only because Nualia promised something,of course the cleric of Lamashtu isn't going to keep her words....so they must enter the fortress unnoticed.

For now Shalelu suggested bringing more help, so Ameiko and Koya joined and they are now going back to thistletop but i stopped the session by that time.

Orik also has already taken the unconscious druid with the excuse he is going to have some fun with her (of course he is not,but he needs to be alone with her to talk their way out.)

Will see how it develops....interesting scenario but a pain in the a**e for a GM since the party is split, and the rogue is going back with more NPCs.