I rarely vote, but I'm for this. I don't know how elves do things in this setting, but IIRC real-life slavers checked the teeth of captives before purchase, as a quick way of determining their hygiene without too in-depth of an examination. Plus Kerillian already has something shoved in her mouth that constantly forces it open, I don't think hiding a bomb in there will stand up to scrutiny if they decide to keep it. And regarding bombs, while Druuchii are prideful in the extreme, they are capable of learning. Should they discover the bombs somehow, they'll know that someone has been making black powder bombs. Like the humans use. Then they'll start putting two and two together and remembering that the gun-loving human that seems to be an eerily aware and awake Terror is in Hultressa's possession and has rarely left her side this entire time. They're going to suspect something, and as conspiratorial and paranoid as the Druuchi are, it's all too likely that they'll find the rest of the bombs we've hidden away once they realize that human-made black powder explosives are in play.
Things have gone terrifyingly well this whole arc, and I do not want to risk any deviation from the plan lest the other shoe drop. One screw-up here could cause the entire thing to unravel and get us all killed or worse. As arrogant as the Druuchi are, they are still millennia-old survivors of power struggles and secret plots just like this one. Just because our plot involves gunpowder and evades magical detection doesn't make our enemies any less competent at this, and if we give them a chance to adjust, the Ark's collective experience and paranoia will come down on us like a ton of bricks. Or a particularly cursed island.
And of course, there's the fact that as arrogant as Druuchi and elves in general are, Hultressa is one of them. There's nothing that says that she too cannot be blinded by hubris, just as they are, especially since she's effectively trying to take on an entire island of elves that may be even more experienced than she is with only a few people at her back. I have confidence in her abilities, but not so much that I would take any unnecessary risks in such a ludicrously dangerous scenario.
[X] Patience: Too much amiss, and you might miss out on your chance to rescue Sadrina entirely. Horrifically, the Handmaiden might well be worth more to most interested parties than either Kerillian or the remaining Whitewings. On the other, more positively looking hand, if you make sure that nothing is too much wrong with them such as trying to hide bombs in their mouths or anything like that, Hultressa might well be able to more smoothly purchase them and bring them to immediate safety. She is more than wealthy enough, and has announced her desires already, so it can't be taken remiss if she wishes to purchase them. If you judge matters incorrectly, either way, it would be bad for these prisoners regardless. You just have to hope you're making the right decision in letting them be as they are, even if it is only for a short while longer.