I love your ambition level. It was fun to watch. I also feel a responsibility to give (and appreciate receiving) thoughtful and constructive critique, which I feel there’s never enough of in this field.
The editing is tight, technically. The storytelling has been put on the back burner a bit, maybe?
The story seems to be that he’s been in the field gathering clues, and this is the moment where he puts them together and deduces “the place”. The unpacking the bag takes a while, and he doesn’t use anything he’s unpacked on camera except the map and the stone disk. One might have less unpacking, but then take a moment to show tight shot a finger sweeping across notes on a page of the book; an ultra tight shot of the cassette player’s wheel turning, a finger tracking along the map with the stone disk and then his finger freezes, as it to signify — yes, this is the place! And then he storms out again.
If all he needed to do was place the stone on the map, and he was in such a hurry — why did he need to “return to base”. He could have done that on the tailgate of his Land Rover.
Anyway, I hope you don’t take it the wrong way — I realize you’ve already shot the footage, and that is what you have to work from. But you’ve got your project ahead of you. The longer finished film will be a collection of the moments you select. Don’t put everything you’ve shot in there, just because you have the footage or because it was in the storyboard. Make sure the shots serve your story. That applies whether it’s a 30-second teaser (maybe especially in a 30-second teaser), or when building the scenes of the longer film.
Best of luck!