Wasn't Renautas behind the summit? Maybe they were trying to lure in evos openly to exploit them, and another party (Angela Petrelli with HRG's help?) took drastic means to stop that.
Well, as I said, it's easier to exploit a group that's hidden and marginalized and afraid to come forth publicly. If Evos were accepted in society, then they could come out openly and protest when they were being targeted, and the law would go after their persecutors. But if they're all branded as terrorists and have to hide who they are, then they'd be afraid to come forward and admit being Evos in the first place, so Renautas would be free to go on exploiting them in secret.
This is why I'm frustrated with all these shows where the mutants or aliens or clones or robots or whoever continue to keep their identity a secret from the world while they're being hunted down by groups that want to kill or enslave or dissect them. If they'd just come forward, let the world know how they're being hunted and victimized, they could win support and protection.
The Tomorrow People last season was particularly egregious about it. The group hunting them was just some corporation; it had no legal right to send out strike teams and hit squads and do all the horrible things it did. But it got away with it because the Tomorrow People kept their existence a secret. So they just made things worse for themselves by hiding the truth. Like so many secrets in similar shows, it was just gratuitously done in order to maintain the conceit of taking place in our world, but it was totally counterproductive for the characters themselves.
It works better here, since the Evos' existence has been outed, but the disaster was orchestrated to turn public sentiment against them, so they have a reason to hide.
I'm just guessing here, but they seem to be setting up that HRG was involved in something pretty bad, that he'd want himself killed before allowing his memory to be restored, and people whom he's trying to help don't trust him.
But he's probably doing it to protect someone, because of something he knew that could cause them harm. Best bet? Claire is alive and hiding, and Noah had his memory of that fact erased so that no one could use him to get to her. After all, this is Noah Bennet we're talking about. The one thing that motivates him most strongly is protecting his family and his daughter. It's
cui bono again -- although it's not so much "Who benefits?" as "What benefit does Noah seek?" And that is always going to be the protection of his family above all else. So that's very probably what underlies his secrets.
I think it's also likely that the remains of the Company are behind whatever's going on with the girl at the North Pole and her invisible friend, since Renautus seems to be after them.
Renautas is after all the Evos, hence the evil Cerebro they invented. But Malina and the invisible woman (was that Shohreh Aghdashloo's voice?) are trying to stop the coming cataclysm, and I got the sense that Renautas is behind that cataclysm.