( Oh dear. It takes only those first few words for Gideon to realise the exact problem, and to know why they're still here. She could understand his questioning over whether or not she was real (she wasn't typically human) but to explain this place as if it were actually somewhere-- )

Captain, I'm afraid that this is still your subconscious. Mr Jackson and Captain Lance were able to depart after you'd believed in them.

( But still he did not believe enough -- in himself, or his memories. A pocket dimension, as much as it was a lovely time and space-y explanation, was not where they were. But it was a start -- he was gaining some confidence still )

But you need to believe still. In yourself.