I'll just slap this right here, you guys can refer to it. I'm fairly certain I exhausted all conversation options, feel free to add to it if you found something. Ignore the "Save 3/4/5" stuff, that is for my reference.
Apologies for the messy layout, it seems f95 doesn't like tab spacing. I'll link my text document as well, says the same thing as this.
To answer your question, it appears to get the sc*t scene at the traffic stop, you need to choose to initiate a fight with Isabel, and then either
a) Attack her until the 'Sexual' option appears, and select 'Sniff Ass'.
or
b) use the 'Speak' option and cry until her patience variable reaches 0.