Akinu: Curses Whitebeard isn't going to fight his allies like I had hoped.
Sengoku: Akinu your strategy succeeded in injuring Whitebeard but you and I both know that a simple stab as that won't stop Whitebeard, let alone slow him down.
Squad: Was I truly tricked, but how does that explain the marines only killing New World Pirates?
Marco: Akinu probably instructed the marines and their captains to attack only New World Pirates to make the betrayal all the more convincing. Plus there are A LOT more New World pirates than there are Whitebeard Pirates so it makes sense that it is much easier to target New World Pirates than the fewer Whitebeard Pirates.
Whitebeard charges the front line with amazing speed swining his naganato at the marines sending a huge shockwave at them. Hundreds of Marines are blown away and killed. Akinu lunges at Whitebeard.
Akinu: How dare you break the agreement between us Whitebeard
Whitebeard: I have made no agreement with you fodders
Whitebeard swing his nagnato and misses Akinu, Akinu tries to swipe at Whitebeard but Whitebeard sees it coming and with his fist and combining it with his Quake abilites he hits Akinu. Akinu flies into a stone wall and disappears. Kizaru and Akoji also attack whitebeard but the result is the same. The shockwaves reach Buggy and his followers, the shockwave shatters the ice freeing Buggy and the others leaving them realativly unharmed.
Marine: Even the Three Admirals are nothing compared to Whitebeard
New World Pirate: What should we do?
New World Pirate2: No idea, I have no idea what to believe
New World Captain: FOOLS!
New world Pirates: Captain?
New World Captain: DON'T DOUBT WHITEBEARD HE WOULD NEVER FALL SO LOW AS TO MAKE DEALS WITH THOSE MARINES AS LONG AS HE IS CAPABLE OF DESTROYING THEM! FOLLOW WHITEBEARD!
The new world pirates find their resolve and follow their captains
New World Pirates: FOLLOW WHITEBEARD!
Sengoku however decided to start with the execution because with Buggy's freezing the camera was rendered inactive, and wouldn't work. But unbeknownst to him when Whitebeard freed Buggy and the prisoners he actually also freed the camera reactivating the signal to the Archapelago where everyone was watching.
Sengoku: Enough quickly resume the execution
Executors: YES SIR!
The two executors begin their traditional execution perfomrance, and ready their spears to execute Ace.
Sengoku: DO IT NOW!
Sengoku is getting paniced because Whitbeard is getting close. Whitebeard had just killed ten more marines and is brushing them aside to get to the platform. The executioners finish their routine performance and ready the blades.
Luffy along with Jimbei are charging through a small line of marines but they are slowing them down and they can't get there in time.
Whitebeard: I won't make it in time
Whitebeard is at the bottom of the stand but he can't jump up fast enough
Marco: I'm too late
Marco is flying but he just left the ship and is also too far
Sengoku: I win Whitebeard
Ace watches as the spears lunge at his heart.
????: KAMIKAZE'S WIND VORTEX
A jet of green wind envelopes the two executioners and turning into a twister it bows the two executioners away.
Sengoku: What the?
Garp: I should have known...Dragon
A figure appears out of the shadows behind Ace and Sengoku looks on shocked.
Dragon: Good to see you again father
Garp: I can only wonder what it was that prompted you to show son
Note: this is under the assumption that Sengoku does act as the final camera is shut off, plus Whitebeard's approach would make Sengoku want to hurry it up even more. Agreement, and opposition is welcome.