"Hmm." It's probably true, so she leads the way again.

And after following the track a ways up north they can hear a faint conversation.

"...dangerous?"

    "Of course it's dangerous! One of them carved up Zorru's whole squad!"

"So we should leave it."

    "And leave it to the goblins? No! We take it to the Grove."

It? A mind flayer, perhaps? Except, hmm. He lifts a finger to his lips and does his little trick of hiding in plain sight then draws closer.

The sources of the voices turn out to be two tieflings, red and horned with demonlike tails.

"Let's just leave it!" says one of them.

    "If it allies with the Goblins it will come after us!"

"Why would it? And besides, we'll be on our way to Baldur's Gate!"

And the "it" they're talking about is indeed the githyanki, who seems to somehow have run afoul of the tieflings' trap and is being held in a cage hanging from a tree. And unlike the tieflings, she notices Astarion's arrival, and though her lips don't move, he can hear her just fine.

Get rid of them.

Right, psychic powers.

Do I get a kiss if I do?

If you do not I will hunt you down and relieve you of your entrails when I free myself.

I hadn't realised we'd grown so close, darling, you'll make me blush with all this kinky talk.

If you want to live and not become ghaik you need to get me down.

Ah, that's what I wanted to hear! Positive incentives.

"Excuse me!" he calls to the tieflings.

"Ilmater guard me," exclaims the first tiefling.

    "—hello," says the second one. "Who are you?"

Wow these people's survival instincts are garbage.

"A friend who has come to solve your issues. That gith? Is extremely dangerous."

"...well, yes, that's what we were—"

"And you're clearly unprepared to deal with it," he continues. "Leave it to me. I can kill it—and my friend here better than me," he adds, hiking a thumb in Shadowheart's direction. "But if you stay around you are very likely to be collateral damage. You should go."

    "...but..."

"If it's as dangerous as you say he is," says the first tiefling to the second, "then he's right. We're not fighters, how do you even want to bring it to the Grove? If we bring it down it'll kill us."

    "...I suppose."

"What is this grove you speak of?"

"The druids' Grove to the northwest, where our people are staying—"

    "Nymessa, they may be friendly but you shouldn't just tell people like that!"

"You really shouldn't," Astarion agrees. "Now go."

They look at each other then nod and bow to Astarion. "Thank you, stranger. Selûne light your path."

Shadowheart makes a face but does not say anything to that.

Astarion waits for the tieflings to be out of earshot and then walks over to the trap to regard the gith. "You seem to have found yourself in a bind here, hmm?"

"Enough gawking! Get me down!"

"Say 'please'."

"Never."

"You would expect some more politeness when you're the one up there and I'm the one down here."