The problem is that you only roll once they leave the feywild. Up to that point time between the two planes works in sync. You effectively just time travel when leaving depending on the result of your roll.
Ahh, true, so it wouldn’t help if you intended to return to the prison before the 9.5 year term was up. You’d need to instead wait for your prisoner to get out and return from the Feywild themselves, in which case it potentially buys you more time to prepare but may backfire
The problem is that you only roll once they leave the feywild. Up to that point time between the two planes works in sync. You effectively just time travel when leaving depending on the result of your roll.
Ahh, true, so it wouldn’t help if you intended to return to the prison before the 9.5 year term was up. You’d need to instead wait for your prisoner to get out and return from the Feywild themselves, in which case it potentially buys you more time to prepare but may backfire