She was singled out specifically among the hostages. They may find more "singled" out.
Hamas wants to incite rage, they want the invasion as it gives them the chance to fight against the IDF directly and use every trap they have. And have the chance to inflict even more casualties. And with the dead civilians from the airstrikes, granted, they were being used as human shields, this drives their recruitment.
Add the increased settlements with the PA being powerless to stop it, this makes them look like the real alternative. Not to mention it rips a giant smelly fart in the small room of possible Saudi and Israel normalization, so everyone clears out. They probably think with this massive act of violence they can extract major concessions and wear down the will of Israeli's. However, I think they may have miscalculated this time.
They were also on to Bibi's game of making things just tolerable for everyone in Gaza. Bibi enabled them because he hated the idea of a Palestinian State with a passion that defied reason. And he got complacent, trying hard to become Putin-lite he missed everything due to his hubris.
Now Bibi has a huge problem, all his years in power will be permanently tarnished by this horrible tragedy. So now he has no choice but to slay the monster he kept fed because he hated an idea worse, who knows, perhaps he deluded himself into believing he could push all the Palestinians out one day. It's his only chance of salvaging what is left of his legacy.
Worst part, to kill this monster, he is going to have to be savage about it. It will and has turned a lot of world opinion against Israel when it used to have to only hear scorn from other Mid-East nations. Jordan and Egypt are now put into a horrible predicament, anti-semitism is on the rise around the world and violence against Palestinians as well. This isn't the day of seeing crap on the evening news, social media news travels fast and all over now.
He made a very bad calculation and a lot of innocents will die for it. In most wars, politicians send people to die for their failures.