He can do that too. Everyone will maybe not have their choice of food on the way out but they shouldn't actually starve.

Belmarniss eats a lot of bat and gives away most of her ration biscuits.

"Don't like them? Or are you protecting the rest of us from any effects too much bat might have on abovegrounders."

"I like bat and if anybody finds they don't and pukes that's a waste. Rather not carry the faint-looking halfling the rest of the way."

"Is someone faint-looking? I don't think my darkvision measures up to yours."

"The littlest one with the patch in her dress."

Nod.

When the stew has all one way or another been eaten they can keep backtracking to the exit.

And slowly, with some monsters but no real mishaps, they make their way out of the cave system. They emerge midmorning, four days later, slime- and dirt- and grime-coated, mostly grateful for the fresh air and the sun.

Well, some of them know Prestidigitation and are quite tidy, and not at all grateful for the sun, but oh well.

"Getting everyone back is going to be a real pain. Too many to fit them on the carpet."

"I guess we take the roads. You know, I could've made almost this compensation sitting at home scrying."

"You hate scrying."

"Someone should maybe nip out with the carpet and back to pick up food while the rest of us walk."

"I'll do that," says Mahdi.

"How long is it hiking? With halflings, they're slower."

"A couple of weeks at minimum. Maybe we can contact the authorities in Sothis and get them to bring everyone in a bit faster."

She nods. "You might be able to fit all the halflings on the carpet with you?"

"A bit of a tight fit. I guess that's probably better than weeks of walking in the desert."

"And it'll mean you don't have to haul back as much food."

"All right."

"You're going to get on the carpet and go with Mahdi back to Sothis," he tells them. 

Terrified and variously frail halflings start complying with this.

She dumps the last of her crackers on the little one, double-checks the water supply on the carpet.

He can carry lots of water in the bag of holding. 

Off you go, halflings. On down the road, humans.