And some of that is actually misleading.
In some of the grimoire cards the traveler actually tried to leave like it did the fallen.
But something stopped it
And in the grimoire it makes hints that a warmind stopped the traveler from leaving
And of course only warmind we know is Rasputin
English
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No Rasputin had a contingency for the traveller leaving, nowhere in the grimoire does it say they actually did this. In fact since vanilla there has been a card (Ghost a Fragment : Mysteries) where Rasputin in his own words admires the traveller because he didn't hide like he did.