Rachnera Arachnera, our arachne, was rejected by her host family and sold off to the filmmaker. She's sour on humans.
She notices Kurusu's arousal, but suggests that he's only interested in what's above the waist, and repulsed by her lower half.
Nope. Kurusu's a leg man.
When MON arrives, Kurusu think the cops are after him for his (vanilla) assault on the filmmaker the previous episode.
Rachnera takes advantage of the confusion (and Smith's lazy attitude) to get herself transferred into his care.