It's not 100% safe, it's what a reasonable person would consider safe. A reasonable person would not consider running from gunfire to be safe.
But there was no gunfire, no aiming of the weapon at him, and no explicit threat of shooting, as in "stop or else", it was just "stop, we want to talk".
Any threat of the above would be merely an assumption on his part.
I phrased this badly. But their hunting and chasing of him, and eventually cutting him off, along with telling him to stop, makes this an arrest attempt. Now, had they not had guns, it would be a failed arrest, as he could have escaped with reasonable safety. But with the guns, that makes it so that a reasonable person could believe themselves to be detained. Note that other, less egregious cases have lead to false imprisonment in tort law.
I've linked the conditions of false imprisonment before and the "confinement" condition seems very shaky, hanging on a very non-explicit threat of shooting at long range.
It doesn't matter if his response was actually motivated by fear. Instead, it matters if a reasonable person would fear even non lethal harm in such a situation (as Arbery didn't use lethal force). That's a very low bar to clear.
But the whole line of reasoning relies on the assumption that it was in fear for his life...
If he was absolutely correct in that fear, the charge would be absolutely suicidal.
He only could get as close as he did because the two have indeed acted as if they only wanted to talk, rather than shoot him at slightest excuse, or no excuse at all.
And as i mentioned before, with the struggle over the shotgun fear of lethal force becomes a very dodgy issue, as both of them had hands on a lethal weapon while engaged in hand to hand combat.
But for a felony murder, it is immaterial whether Arbery was acting in self defense. If the McMichaels did commit a felony, then they lose all claims to self defense. Then since a death occurred, felony murder triggers.
Perhaps...
But that implies McMichaels gets sentenced for a different felony first. Will he? You seem absolutely sure of it, i'm not. The false imprisonment issue you seem to be pointing at is again far from as clear as you seem to think.
No, it actually doesn't. What it does is remove the duty to retreat. In a non stand your ground case, you could make the argument that Arbery had an obligation not to escalate the situation, and see if he could run. Stand your ground just means removing this requirement.
Arbery would not have to plant his feet in one spot to fall under the protections of Georgia's 'stand your ground' law--running at the perceived threat he saw (whether such was a good idea from a seld-preservation standpoint or not) would fully fall under it as a legitimate action to take as his only method of potentially stopping the (perceived) imminent use of unlawful force that shotgun-man presented to him.
Guess i might be wrong about the legal interpretation of running to close in alone, but...
Looking at the situation from hindsight, he had no reasonable way to stop that threat completely, and if the highest possible assessment of the threat was correct, he would not get nearly as close as he did. In hindsight, shots were fired only once the struggle for the weapon began. If the shotgun man was indeed going to imminently and unlawfully use the shotgun, he had ample opportunity to do so sooner, yet he didn't.
That perception thing what i was hinting at here. That point is to be decided by whether that perception was justified, and that in turn will be based on evidence as far as it is available, including the video. And from the video alone, it seems like a controversial case to be decided on small details, because what we see on the video is not looking like a typical case of "person proceeding to imminently shoot at someone", standing around merely holding the weapon, rather than aiming the weapon at the intended target.
