I enjoyed your chapters - I haven't got to Chapter 3 properly yet. Its a great country choice and I like the idea of her being stranded there by accident.
The first thing that occured to me is does Jane need to feel more? She seems to accept a lot. It takes a while for her to ask what happpened to the plane. I feel like that would be my first question and whether anyone was hurt. I feel like I'd be panicked until I got my head round it all but maybe its the concussion but I thought you could draw out her feelings of confusion/fear a bit more perhaps. If her acceptance is due to the concussion then I'd maybe lean into that and show it more i.e. her head being fuzzy, not concentrating and being dragged into Ulaanbaatar etc. If you up her emotional side I think it would help just draw out some of the tension which may help further down the line. For example, at the moment she doesn't have much option but to go with Tenzig but surely she could have the option of staying in the airport or at least say she will sort herself out to the strange man? Could the egg-dream story (which I really liked) be the push she needs to commit to going with him? Maybe that doesn't fit but I feel like it would be good if she had a bit more agency - a dilema to make a decision on that pushes her to the next stage. It may help increase the tension later on too.
The other thing that ties in with this is the feeling of a culture shock from Ulaanbaatar. I think you could draw her feelings about the place out a bit more just to make the reader really feel like they are there. Having been to Mongolia as well as Japan and China I think there is an immediate feeling of being somewhere very different to anywhere else. You have some great details but you could make the reader really feel like they are there with Jane experiencing it - the shock of the cold against the skin (it bites doesn't it?) the smell of all the woodburning everywhere, the austerity of the city buildings etc. At the moment she takes it all in her stride, explaining the detail - which might be what you want - but I think you could make it more vivid/immersive.
Anyway please feel free to discount all this as it is all subjective! :D You have a great start. And for the record I feel a little like a fraud in suggesting adding more emotion as I have had this exact suggestion about my own work recently - haha - but I think it is so much easier to see things in others writing than your own, particularly when your eye is atuned to one element! Hope this helps!