Always torn between Swap/Swapfell Sans being the in the Judgement Hall or Swap/Swapfell Papyrus because they’re both such good options?? (I’ll be talking specifically about Swapfell for the rest of this tho)
On the one hand, it makes more sense for Rus to be the one waiting so long to take a stand. He’s lazier, less willing to fight, and he’s still got some hope left.
In that same scenario, Mal would absolutely be the first to attack the human. He has a job to do and he’s going to do it, especially if the human is killing people. Except he fails.
Rus waits to fight, at first because he believes there’s some good in them somewhere, but then because he’s fucking terrified. His brother, Captain of the Royal Guard, the queen’s right hand, who can warp spacetime, was killed by this human. Rus is alone, with no one he could truly trust to protect him, crippled by the devastation of losing his only family. So he waits for Alphys to take care of it. Then for Napstabot and Undyne, or Grillby, or anyone… until it’s just him. And by then he doesn’t have a single thing left to lose.
Alternatively, Rus has hope because he talks to Asgore through the door. He hears about the human ahead of time, and how they’re just some lost kid, and when they come through the door with dust on their hands, he understands. Or at least thinks he does.
They’re just a kid, scared and alone, defending themself against monsters that are bigger and scarier than they are. Rus has been there. So when this kid heads towards Snowdin, he shoots his older brother a message asking him to wait. Hold off on attacking this human because they’re just a kid! Maybe Rus could talk to them and for once, no one else has to die.
So Mal waits. He doesn’t like it, but his little brother is finally setting his sights on doing something important, so he hangs back.
Rus stops the kid on the outskirts of Snowdin and tells them it’s okay. They can stop fighting because Mal is in charge of Snowdin and they’re safe. But the human was never after safety.
Mal sees his brother die at the hands of this human and his world shatters. He only had a sliver of hope left, and what’s that worth now? Why even try?
He doesn’t even warn Alphys. He watches the rest of the Royal Guard fall one by one as the human marches farther into the Underground. He can’t find it in himself to care, until they find him in the Judgement Hall, disheveled and apathetic.
All that’s left between this human and their goal is him. He let them get this far.
Mal understands that just as well as Rus did, but he always had a reason to suffer. Mal had a little brother to look after. Every awful thing he did to survive, he did because it wasn’t just for him. Then the human looks him dead in the eyes with a smile, and he realizes: they have no fucking reason other than cruelty.
That’s what makes him fight.
