Peter answered him, “Though they all fall away because of you, I will never fall away.” Jesus said to him, “Truly, I tell you, this very night, before the rooster crows, you will deny me three times.” Peter said to him, “Even if I must die with you, I will not deny you!” And all the disciples said the same.
— Matthew 26:33-35
Could Peter have stuck to his guns and shown Jesus that He was wrong?
Good question.
In other words, could Peter undo the specified events of history in the making, as we see in time travel movies?
Since Peter was Peter, Peter could only be Peter.
To explain, there is a personal flaw I am battling to overcome.
God knows this. God even knows me better than I know myself.
So, say a situation comes up, which will challenge my ability to deal with effectively, because of failing to overcome this flaw, God can tell me exactly how I will act in the situation.
Couple that with the fact that God can, in an instant of time, see ahead to the exact time the challenge comes up, he can instantly prophesy the future event... and I cannot change it, because that's me.
Jesus saw Peter. That's Peter, with his personal flaw, which he was not winning the fight against... that is, if he realized the flaw.
However, he did not, because he was not aware that his impulsive nature was a flaw.
Repeatedly, Jesus tried to show him, but he did not see it.
So, much so, that when Jesus was in the garden, and told Peter, James, and John to keep watch, and pray, so that they don't enter into temptation, they fell asleep.
Can't blame them entirely, because they were grieved, but nonetheless, Peter failed to pray like Jesus did, in order to see his flaw, and know how to correct it.
Peter was a work in progress. So am I, and what I am saying here is actually instructions for me, and a lesson I should learn.
I really need to pray more, and do so in the manner that Jesus did.
So, in summary... Peter had no guns to stick to. Peter had talk. You know like they say, all bark and no bite.
Peter would have fired blanks, or water, or went "POW. POW" with his mouth, as he waved his fake gun.
Don't get me wrong. Peter was sincere. He just was not able to see the flaws that would get in the way of living up to his sincere intentions.