I doubt any 4D STS would flee from us. We are nothing to be afraid of. They probably see us kind of like we see creepy little animals. They might try to scare you, as your fear would presumably be good for them, but if they could see you're not afraid of them and that you actually have an idea what they are, they'd just leave you alone and go about their business, whatever it is. I don't think we're worth much attention to them individually. Just like a single sheep isn't worth much attention to most of us.
But I've heard all kinds of stories about people confusing the greys with various actions or questions. Of course I have no idea how accurate these accounts are, but it seems like the greys (or some of them) are not entirely autonomous and can be easily confused, so you can actually mess with them if you don't lose your cool. All these stories are anecdotal, but it's a fun concept. At any rate, I suspect the presence of the reptilian types can be rather terrifying even if you're 'ready' for it. Probably wouldn't be too pleasant to meet them. (Though I would like to have the opportunity anyway.)
If we ever get to a point when we'll start seeing them and will still be able to talk about it here, it should be pretty entertaining and exciting.