It's funny how easy it is to imagine Arsenio getting by simply by being friendly yet thinking it's because he was skilled.
And then sad when you realise how quickly people forgot all about that the second they saw him as a monster.
It's no wonder he's so devoted to Betty. Just look at his face when he asks her to believe him. He's desperate there, yet look at how much rejection he has already had. He probably doesn't even expect her to help him in the first place, he's just trying on some small bit of hope. And she basically said yes with a smile, the first person to not be afraid of him. Even Vivian there saw him as a monster first and foremost, yet she saw him as simply someone in need of help.
Also the idea Vivian can track Betty makes me think this is not a rare thing for Betty to go off when she's told to stay put.