It was established that the Box blocks everything from outside world, so it shouldn't be possible to get GPS signal from inside the box.
At the start of the episode Amanda is wearing boots with quite high heels. However, when Jason is carrying her in the snow world she is suddenly wearing shoes with flat, profiled soles.
At one point while in the Box Jason uses a satellite telephone to get GPS coordinates. But the whole point of the Box is to isolate the interior completely from even the slightest connection with the outside. GPS signals must not penetrate the Box or else otherwise it could not do its job.
In Are You Happy in Your Life? (2024) Ryan says that his and Jason's rich friend from college named Andrew Darab is his partner and investor, but here it is revealed that Ryan's rich friend and investor is in fact Leighton and "Andrew Darab" is never mentioned again.
Jason confirms that the GPS device works-the satellites can be reached while inside the box (12:02)-despite the box being made of "active adaptive shielding" that "cancel out whatever radiation or sound tries to make it inside" (S1E3 17:27).