He wouldn't walk me out?

I hung out with this guy, I guess I'm seeing, and was about to leave and we said bye, and as the door was closing I heard his sister say "walk her out" and he said no, in a kind of rude way. I don't know if that's a red flag or not. I'm really freaked out about guys using me, so that kind of set me off. I don't think I was supposed to hear or if he knows I heard. Is that a bad sign? He never walks me all the way out, just to the door.
He wouldn't walk me out?
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