As much as Barry doesn't want to mess with the timeline. He isn't going to let these people gas hundreds of innocent people.
If this has some impact to the future, then fuck it, fuck the future. And if things turn out way worse than it was before, he can always come back to this moment and stop himself.
Barry runs up to the soldiers and knocks them out one after the other before they even know what hit them; they are already lying on the ground unconscious.
Barry then puts his hands on the cannons and begins vibrating them at such high intensity that he immediately destroys the molecular structure of the cannons and turns them into powered metal dust.
He does the same to all the other cannons.
No cannons, no firing mustard gas, no innocent lives taken.
"I should get back to Diana," Barry says and disappears before appearing inside the hall once again, only to see Diana storming out in frustration as Steve chases after her.
Barry runs out of the high command building and appears right before Diana, stopping her in her tracks.
"Diana, Steve, wait. I found the gas," Barry says.
Hearing this, Steve rushes to Barry and grabs him by his shoulders. "You found it? Where is it?" Steve asks.
"Under the high command, a large storage facility, containers of gas waiting to be deployed," Barry says,
"We have to destroy it," Steve says.
"Then we will have to wait till for nightfall till everyone leaves," Barry suggests.
"No, we don't have time. We had to destroy it now," Steve says.
"Are you out of your mind? There are people inside the high command right now. We can't do that," Barry says.
"They are Germans," Steve says.
"So what if they are? What about the ones who are innocent? The ones who never wanted to be part of this. Should they deserve to die as well?" Barry asks.
"If I kill Ares, this will all stop. I need to find Ares," Diana suddenly says, grabbing both Barry and Steve's attention.
Barry looks at Diana and believes her, but he doubts if this Ludendorff is really Ares. It can't all be that simple.
"Diana, stop it! There is no Ares. This is all humanity's doing. No one is being manipulated, no one is being corrupted, everyone's at fault here. It's all our doing. And if we really want to stop this war, we need to destroy the gas before the Germans use it and escalate this war even further," Steve says.
"You don't trust me. This is all Ares's doing. He is putting doubt in your mind," Diana says, sticking to her belief. "Barry! You believe me, right?" Diana asks, looking at Barry, when suddenly they all hear shouting and then a loud boom.
All three turn their head and see some soldiers firing a cannon from one of the towers, and the target is the same village they just saved yesterday.
More cannon shots can be heard from other directions.
'How is this possible?' Barry asks, as he is certain that he had destroyed that cannon and knocked those guards unconscious.
"I need to go," Barry says, and disappears before their very eyes.
Diana also makes a run towards the village on a horse while Steve gives chase.
__________________
"How is this possible? I am certain that I destroyed those cannons. I made sure to double-check it, so how is it intact again? Is Diana right? Ludendorff is Ares? Is he the one doing this?" Barry thinks at super speed as he sees the massive gas bomb slowly hurl towards the village.
'How do I stop all of them?' Barry begins thinking while being in Flash Time. His mind is working faster than it ever has.
"Yes. I need to first explode them and then trap the gas inside a vortex of air," Barry quickly comes up with the best idea he could think of at the moment.
He grabs a small stone from the ground, aims it at the gas bomb, and throws the stone at it with speed reaching faster than any bullet fired from a gun.
The stone easily pierces the bomb container, and before the bomb can even explode, Barry runs around and super speed, creating a powerful vortex of air, trapping the escaping gas from the bomb in a small area.
Barry then immediately makes a run for the other bombs and does the same thing again and again.
If one looks from afar at a three-four-mile radius, one would see multiple tornadoes conjure out of thin air, all at the same time across multiple areas.
Diana, on her horse back sees the tornado and makes her horse stop. She sees the tornado mixed with some foreign gas. She realizes that Barry has managed to stop the bombs from hitting civilian areas, making her sigh with great relief.
But she doesn't stop. She continues her way towards the village and finds it intact.
"Diana, you are here," Barry suddenly appears before her and takes a deep breath to calm himself down.
He pushed himself out there so that he could catch all the bombs before they hit civilian areas. It's probably the fastest he has ever run because he needed to create multiple tornadoes at the same time across miles of distance.
Seeing Barry, Diana gets off her horse, walks up to him, and gives him a hug.
"Whoa, what's this about?" Barry asks, caught by surprise.