Ground gets destroyed, bye goes the marking.
If you move a black hole 20 meters away from you the outcome will be no different. The entire solar system(s) is/are made of interstellar gas. Gravity's force compresses individual atoms of interstellar gas. It's either he takes in the entire gravitational field and it is entirely redirected as one piece to kill him, or he somehow takes out a small piece of the gravity right in front of him, in which case the 'two sides' of gravity which were separated by Minato would gravitationally attract one another and reform instantly the second it leaves the space-time rift. Since he's right behind the barrier he still dies to it, in this way, or the previous way. This is also all under the assumption Minato can react in time to such a CST when he has no intel on it (Naruto didn't, he only knows Nagato destroyed Konoha, he doesn't know how.
We aren't talking about a black hole, also not sure why real life logic is being applied to a technique that can tear open holes in the air and be reopened else where. The technique has seals all around the barrier, it's clearly a type of sealing jutsu as well as barrier.
Also don't understand how minato dies from behind the barrier, nothing is getting to the other side of that barrier, everything passes through. The barrier attracts, ST repels. ST moves towards the barrier, while the barrier merely pulls in what was already heading for it. It's almost like an invisible projectile. There's nothing more to it than that, no need to over complicate something that doesn't apply to real world logic, this is ninjutsu, not astronomy. That force is then released in another location.
Katsuya/Tsunade reacted to CST. She shielded and covered everyone before it hit. It's a bait and obvious move. Requires a lot of chakra to be gathered, it wasn't something Pain did instantly. The regular ST would be harder to react to. Not to mention this is assuming all the other paths are killed. He isn't gonna take out his other paths , whose to say minato doesn't take out deva first.