Looking for advice/ just to share a situation that kinda made me feel uncomfy.

I (F), have met this couple (MF) once before. I saw them for the second time recently.

Before we met I'd known that they're into lots of bdsm play inc knife play. We talked about it, and they said they'd used a butter knife before and I said it sounded like fun.

The first time we met was lots of fun. The second time, during the session, the guy told me to lie back and close my eyes while the girl played with me and he went to get something. I heard him come back in the room, and he sat on my chest and I felt something metal on my neck. I assumed this was a butter knife and I was surprised but okay. He asked me if I liked it and I said I did. He moved it down my neck/chest and then I opened my eyes.
He had a large kitchen knife.

I didn't say anything immediately cause tbh I was a bit shocked and I'd already said I liked the feeling so kinda felt like I couldnt say anything? He put it down less than a minute later.

I didn't really think about it properly until I left and I'm feeling really weird about it all. We'd never discussed or planned for that to be part of our play. We'd had a brief discussion about safe words, but hadn't actually confirmed any (stupid I know). We never talked about any aftercare. I (again stupidly) thought this didn't matter as much because we'd never planned on doing anything more than pretty vanilla sex.

I feel like such an idiot, and almost a little violated? I dunno.

Am I being silly and thinking too much into this?

I know I should have said something at the time, which makes me a bad sub, but we hadn't agreed to any dom/sub scenario either? Should I see them again with better chat before? Should I end things with them? Any advice would be great