Two young Thai ladies are about to crash into a foreigner twice their size.
The accident is going to knock a mobile phone out of the hands of one of them, resulting in scowls and an apology from the wrong party.
That surprising incident will happen at the very end of this column, a good 20 paragraphs away, so let's pick up on their conversation just prior to the event.
These two girls are dressed in Bangkok suburban chic; flip-flops and oversized T-shirts with giant English lettering, one of which that reads CUTE GIRL. I am reminded of the 1980s when Frankie Goes To Hollywood was all the rage, and we wore overpriced T-shirts with such pearls of wisdom as FRANKIE SAY WAR IS BAD and FRANKIE SAY BIG SHOULDER PADS ARE HIP. I made that second one up.
These girls clutch smartphones and their gazes flit between those phones and the other friend.
''He's gorgeous!'' the one with the round face and lack of chin is announcing, while her friend shoots her a look of dismay.
''Gorgeous? You know he's a bad guy in real life!'' she replies. She is skinny and the prettier of the two with a pink hairband that complements her gums when she scowls, as she is about to do in a minute.
''He ditched his girlfriend in real life, you know, and is now seeing someone else ... you know?'' She uses the Thai roo mai at the beginning and end of every sentence, much the same way we Queenslanders say ''y'know?''
The formless friend is aghast. ''No!''
''Yes! They were seen out together at RCA two weeks ago. And he didn't tell his girlfriend, who was in the States at the time. Here. I've got a copy of the picture taken at RCA somewhere here. I'll find it for you.''
What soap opera are they discussing? I haven't a clue. Besides I don't want to get into the conversation. I just want to get past.
The two girls and I are standing together on the mother of all escalators, at the Big C superstore on Rama IV Road not far from Channel 3, which was probably broadcasting that soap opera. I host a radio show in the TV station building so I do have a good introduction if I wanted to enter their conversation.
(''Excuse me, ladies, but I couldn't help but overhear what you were talking about, and I just wanted to let you know I'm heading to the building that is broadcasting the very drama you are talking about!'' I don't know which is worse; being perceived as a nerd or a sexual predator.)
But back to the Big C Rama IV escalator.
It goes up the equivalent of three storeys. If Thailand wants to ever be the hub of escalators, then the AGMs should take place right here.
It is an escalator that resembles a Thai soap opera itself; long and slow. You'd think with such a distance to cover it would travel quickly. On the contrary. I can't think how long it would take just to stand on that thing and allow it to haul you up, with the strength and speed of a slow loris. Well yes I can think. Because I am forced to do so every time I visit.
What compels seemingly normal people to stand still, blocking the traffic behind them, like these two girls are doing?
Is it the demographic here on Rama IV? I mean, this is not the area to set up a card table to accept applications for Mensa; the neighbourhood is made up of slum residents and TV folk.
I go there regularly thanks to its food hall, especially the som tam shop and the lady who makes fruit shakes. But between those fruit shakes and my car there is that mega-escalator, and try as I might, I always end up behind people in a giant hurry to nowhere.
I had an American friend who would get furious about this.
''Th-tand to the right!'' he would bark at a volume that would jolt otherwise stalwart women and children. (My friend had an unfortunate lisp and spoke with a nasally shrill voice when he was peeved about something, which was all the time when he was in Thailand. Other than that he was a really lovely guy.)
I could never be so brazen. I could never bark ''Stand to the right!'' any more than I could bark ''Stand in line!'' or ''Stop picking your nose!''
First of all, isn't it left? This is not another example of my ignorance. It turns out the whole world knows that you stand to the right. With the exception of one country. Australia.
Are we then singularly responsible for the global confusion, thanks to our propensity to spread our wings and travel?
Certainly in Thailand they are confused. Some people stand to the right. Some stand to the left. The vast majority stand smack bang in the middle, two or three abreast, and talk about soap operas.
The Big C escalators are more insidious because they are not step escalators. They are those smooth ones to accommodate shopping trolleys.
Those trolleys when positioned to the far right still allow enough space for customers to hurry past. But does anybody position them to the far right?
I believe in the law of attraction, because every time I approach those escalators I attract families of four with overflowing trolleys getting on seconds before I do.
I did a quick internet search before writing this article, and guess what? It's not just Thailand. This is a global problem!
All around the world people are barking ''Th-tand to the right!'' at others who block the way. The BBC ran an article about ''escalator etiquette'' which should be translated and sent to the ICT Ministry for immediate dispersal.
Recently I have taken a leaf out of my strident American friend's book, thanks to him sending me a Reader's Digest article about being more assertive.
I have started saying ''excuse me'' to people who block my way.
When I do, half are unaware of the crime against humanity they are committing. There is a look of bewilderment on their faces. I almost feel I need to apologise for upsetting them.
The other half tug even more at my heartstrings. They express remorse. They are truly sorry for standing in the way, and apologise, which makes me respond with a mai pen rai.
Thus I am in a no-win situation. By allowing people to block the way, I end up angry and resentful. If I barge through, I end up apologetic and looking like a bully.
''Don't be tho wishy-washy!'' my American friend would say if he heard me express that thought.
So why didn't I say anything to the two girls? I notice that in front of them there is a family of four splayed across the escalator. Further up is a shopping trolley. A group of schoolkids in front of that. God help me if World War III breaks out while I'm on this escalator. I'm dead before the evacuation sirens even start!
So I lapse into my own little world, instead casting my full attention towards the giant green and red Big C billboards depicting happy shoppers as I glide upwards.
''Here. I'll send that pic over to you on Line,'' says Prettier Of The Two.
''Great, thanks,'' says Moon Face.
And they stop.
At the very top of the escalator.
Oblivious to anything behind them.
They concentrate on the all-important task of locating a picture in their smartphone's camera roll and _ crash.