My theory is as follows:
There are 3 Different plains of existence, 3 different dimensions if you will.
Normal, our everyday dimension.
Kamui, pocket dimension created by Doujutsu.
FTG, pocket dimension created by 'Ninjutsu'
Now. In ANY circumstance where a person is trapped in Kamui dimension, and doesn't have access to Kamui/FTG themselves, they are screwed beyond belief.
But my understanding is that, since a user of FTG transcends the "Normal" dimension, into their "FTG" dimension briefly, and pops out at a designated location. I see FTG as a 'plausible' out for someone trapped inside of another users Kamui dimension, due to it carrying the same implications as when an FTG normally uses the technique to teleport.
But then that arises the argument of whether a Kamui dimension cuts off use of Chakra, or Jutsu, or any and all connection to the outside world.
https://www.youtube.com/watch?v=BumJgOkFJ7MLook at around 11:36, you'll see gaara's sand lose shape as Sakura and Naruto enter the Kamui Dimension, which either means that gaara couldn't control it inside of the Kamui dimension, or simply saw it fit that he didn't need to carry them around anymore. Whatever is decided from that could be pivotal to the overall success or failure to the defense/plaintiff.
But to me, still there is question whether since it was Ninjutsu that gaara uses, is why his connection was cut off. Since Hiraishin is Space time, it could be different.
This is all speculation, and I will say it clearly, I do not know, because it has never been shown.
TL;DR: With FTG, probably.