Samus has insane levels of willpower. The suit itself takes tremendus concentration and will just to maintain. Samus doesn't will it off of herself, she stops willing it on.
Heck, when Samus was corrupted by phazon (this stuff corrupts planets, BTW) and had 99% of her body converted into the stuff, she stayed sane and kicked ass. Several other named characters succumbed to this (including Ridley), but Samus didn't. She's shown considerable resistance to psychic, dimensional, and magical attack.
By worse than mind rape, do you mean head asploding or what? When I hear the term I tend to think mind control, memory erasing, insanity causing kinds of things.
Sounds very No-Limit-Fallacious. Ysera break through highly resistant minds in her sleep. Did I mention she utterly destroyed an invading army with a thought, despite the invading army being resistant to anything effecting the mind? Demons actively prove this, at a daily basis.
Just because Samus failed to take in the telepathic message, does not mean she can withstand a full-scale assault by Ysera. You need to do better than blocking telepathy.
There is a wall between Samus' mind and Ysera. The strength of the attack does not matter if the attack cannot reach Samus' mind. That is my point. It's like trying to X-ray a lead box, to give a not-entirely-accurate-but-still-getting-the-point-across simile.
The shield caused the telepathy to miss, basically. In order to recieve it, Samus was forced to "intercept" it before turning it into an understandable form. It is quite likely Samus has mental resistence, but there is a literal shield that prevents things from reaching that far. Psychic attack is based on what happens when it reaches the mind, not getting to the mind in the first place, which is what Samus' defense is based on.
Not sure what it is you are not getting: Demons display barriers to mental attacks daily. Ysera destroyed an invading army of demons. "Not having been broken through so far" is not adequate enough an argument to claim Ysera can not touch her.
Just because meager telepathy could not touch her, does not mean an offensive move by Ysera can not. Not that I have yet read any implication that Ysera could not brute-force herself through Samus shield, even should it attempt to block.
They way you said resistence implied that demons had powerful minds. Many spellcasters and such do I was not aware that they could create barriers to shield their minds. That's it, right? So, did Ysera simply destroy these barriers or bypass them entirely?
Samus' shield only slightly avoids a No-limits-fallacy in the way it works. When I say the shield has not been pierced, I'm not saying the attacks in question bounced off. Far from it. The shield expends energy in order to repel attacks, and can repel any attack- provided there is enough energy to do so. When I say "not been pierced", I mean the nothing has simply ignored the shield and hit Samus without draining the shield first. There are at least 2 instances of something forcing the shield to expend all it's energy and then hitting Samus: getting corrupted by phazon and infected by X. In both cases, the shield's energy hit 0 before anything happened to her.
Whatever Ysera wants to do to Samus mind, she must first do to the shield. It will expend all it's energy fending off the mental attacks if necessary. Ysera will have to force her way through the shield in order to get Samus. You hit it with enough power enough times, it will go down. But by that point, Samus would have lost already.
The narrator never specified if it bypassed or broke, but neither speak in favor of Samus. We know that demons have a mental barrier that keep them "safe", something we not only see in the games but we also read in The Last Guardian. Not even Medivh sensed the presence of a demon when it walked through his hallways.