Any motion> lack thereof. Or happening at the same time. She still has to find mewtwo's actual location with her visors as well.
Built-in radar and map makes this the least of Samus' worries.
You also gotta remember, to home on mewtwo (which is required at this range to hit anything) she's gotta lock on.
Auto-targeting is fun.
All of which takes precious time, time samus doesn't have.
Why not?
For example, the suit is not immune to be dismantled, major portions of it were removed by surgery in metroid fusion. Mewtwo can use telekenesis to do the same thing.
You do not have any proof for that. You're also making an assumption that Samus Aran's Power Suit can be dismantled just like that. The problem with your assumption is that during the time when Samus' Power Suit was being surgically removed, she was unconscious. She'll be conscious during this battle.
He also has telepathy to puddle samus' brain.
This is another assumption, and so far, I haven't seen anywhere in the Pokémon series that Mewtwo has the ability to "puddle Samus' brain." Furthermore, I can equally assume that Samus' helmet is like that of Juggernaut's, making her immune to telepathic or telekinetic attacks. But, you would be asking for proof, now wouldn't you? Of course, you'd have to back yours up, or the both of us can go with the logical fallacy of
argumentum ad ignorantiam. After all, we are going by canon, are we not?
And need I rememind you that he can take a half-instant out of his day to go "bull in a china shop" with the internal mechanism of samus' arm canon, ensuring that even if she does escape, she can't fire anything.
Proof of this ambiguous assertion, please?
And you gotta remember that if samus cracks off a shot, her beams can't go through everything, at least the ones that can actually home. Almost all the corruption beams stack, but they can't go through everything.
In Corruption, the Wave Beam was not present.
The 2D metriod beams stack, but they can't home, they can go through stuff though.
And none of the other 3d beam really are particularly useful alone.
In Metroid (NES) and Metroid 2: The Return of Samus, Samus is incapable of aiming diagonally. In Super Metroid and Metroid Fusion, she can aim diagonally. Which one are we going to choose? We can't choose both, right? Why is this relevant? Because, this is exactly what you're doing here. In the side-scrollers, none of Samus' weapons home. In Metroid Prime, the Wave Beam and Missiles homes in on Samus' enemies. While we're at it, Samus' Wave Beam cannot go through walls and objects, because this does not occur in Metroid Prime. I have a problem with this.
Samus is in the Metroid Universe. The Wave Beam can home in on enemies. If Metroid Prime had been a side-scroller, I doubt this feature would have been present. So, I don't see why Samus cannot be granted to have her Wave Beam fire through walls and objects, as well as home in on her enemies. It's all in the Metroid Universe, and it's not mutually exclusive any more than Samus being capable of aiming diagonally, though this feature wasn't present in the first two games.
The point being that mewtwo can use psionics to mount a defense even if samus gets a shot at ultra-long range. None of the beams are instantaneous in reaching their target.
But they're quite fast, and a hit is inevitable.
As I explained before, pick the appropriate places to hold, and you can hold with almost no effort.
Samus Aran's Power Suit is quite heavy. In Metroid Prime, when you scan a pole that brings up floating platforms, if you scan it, it says that it cannot hold the weight of Samus' Power Suit, which is the reason why you have maybe a second to jump onto the other platform before the one you jumped on falls. It is also mentioned from the trophy, Samus Unmasked, that "even burdened with her heavy suit, Samus is as graceful as a butterfly."