In the movie "Species" is the woman that Sil holds hostage the same woman she met in her car at the grocery store?

It's been a long time since I've seen this so I'm not sure if I'm answering your question or not. I thought when Sil was naked, she got in a car with a women. Then later, the next day, that lady from the car has been tied up and Sil is at her house. Sil cuts off her own finger and the lady's finger. Then later that evening, Sil puts the lady with a missing finger in the car that goes over the cliff but Sil's finger is in the car and they find it and assume the burnt body in the car is Sil.