You can't "break" open a barrier made of nothing...it isn't even a barrier, its more like a portal that sucks things in and teleports them to a new location.
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We don't know enough about the technique just yet. Clearly from the panel we see that the TBB is engulfed by the barrier BEFORE he decides where to send it. So where does it reside? My opinion is that it resides within FTG seal of his kunai, ready to be unleashed. If there's one thing we learn from Naruto though, is that every seal has a limit. A TBB would likely bust it open and vaporize Minato. Therefore he had to quickly teleport it before it did detonate.
C says on the next page it ignites whatever the use is looking at and the panel shows Amaterasu appearing where A is.
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Whether it's a projectile or that is has a lag between when it appears and when it sticks to the target, it doesn't matter, Minato has the speed/reaction feats in the manga to avoid it. Minato is smart, he wouldn't get caught by something, even if he hasn't come across it before (e.g Obito trying to suck Minato into other dimension).
If Sasuke covers the majority of the field with flames, there is nowhere for him to run except a spot that isn't covered, which leads to him having no where else to teleport to meaning he gets finished off. He gets out of one area and Sasuke keeps on spreading the flames.
Not to mention Magatama can fry his Kunai anyway so there will be no escape.
Like I said, Minato can just stay on the edge of the flames, and sasuke will eventually run out of chakra if this is all his plan is. All that amaterasuing everywhere and using enton Control will burn him out after a short while. For minato it's just casual FTGs between kunais and picking them up before they can burnt, kiting him outside of the border of flames, keeping his eyes down at the feet, until sasuke's susanoo crumbles from lack of chakra.
Then FTG backstab, rasengan to the FACE