There's a relevant book that I've posted about elsewhere so I'm just going to quote myself:
A person who responded to me put it even more succinctly:
So I completely agree with you. These people will take any attention, good or bad, as encouragement. I don't think it's fair to cast every person experiencing "gender dysphoria" as mentally ill (hey, I'm tolerant to a fault), but the vast majority of them certainly seem to be, especially the ones who harass people online and aren't just quietly living their lives and trying to get along. Don't engage them, just steer the fuck clear.
So the book I mentioned above has as its main thrust the concept that we have a capacity to recognize threats and feel fearful without necessarily being able to articulate why, like a gut feeling. Society has taught us to repress this feeling, taught us not to be prejudiced against men, against black people or just to withhold judgement unless the person is explicitly threatening us. We are strongly socialized to follow social conventions, even though we have a gut feeling that something's wrong, even very wrong.
I believe that's the reason you stayed in the bathroom to wash your hands. Five years ago you say you would've screamed, but this time you stuck around. You've been socialized into ignoring your senses and your judgement. And by doing so, you gave the troon an opportunity to engage you in conversation and you felt obliged to respond to him, even non-verbally, when he tried to engage you in conversation.
Something predators often like to do is to engage a potential victim in conversation. I tend to view strangers approaching me to ask for cigarettes, directions or the time as potentially the beginning of a robbery or an assault. They expect you to follow social conventions and oblige them, thereby giving them the opportunity to size you up and to close the physical distance between you. They'll see if your voice or body language is assertive or if you're hesitant and will let them get close enough to punch or grab you.
Also, I don't know if women tend to socialize in public restrooms, but as a man I can't recall a stranger ever speaking to me in a public restroom beyond words like "pardon" and "thanks". Maybe women tend to socialize more, I don't know, but my distinct impression is that troons have weird ideas about what goes on in public restrooms and expect lots of social interaction to go on in there. There's even the one fucked up troon ("Yanniv") who kept asking about what he's supposed to do if he finds a lonely child in distress having her very first period in a public restroom and if he's supposed to help show her how to put in a tampon. I'm retching as I type this.
My point isn't that we should walk around paranoid all the time. Nine times out of ten, the stranger asking for a cigarette probably just wants to smoke. But what you should do is trust your instincts. Next time you find yourself alone with a tranny in a desolate public restroom and your gut tells you to get out of there, don't stay and wash your hands, don't engage them in conversation, and if you feel the need to break into a run then do it. If you were to read this book you'll find accounts of women who are dead because society taught them to be "tolerant" and to ignore their instincts.
I'd also like to recommend the following article by The Last Psychiatrist,
When Was The Last Time You Got Your Ass Kicked? It describes a scenario where the protagonist feels he has to follow social conventions and respond politely to an aggressor even though he's absolutely aware that he's just being humiliated and is being set up for a crime.
Anyway, sorry for typing out a novel. I just think it's important to encourage people to break social conventions and trust themselves even if society tells you that you're "intolerant". Behave with as much "tolerance" as you have to to keep your job and not get ostracized, but never let yourself be blind.