For every failing sun, there's a morning after.

Frank planned it for days, weeks yes, even for months.
He planned every detail and created several back up plans for the case he would somehow fail this mission. It's unlikely that anything can keep him from doing so, he was absolutely sure this would be the only logical solution to his problems. The only decision people would approve.
He's already seen too much of this fucked up humanity to keep going like before.

Nothing can change his mind anymore.