attempted pickpocketing and knife flashing

So on the way to go to the ´interactive museum´ there was a guy with super short hair, short and super skinny. Anyway he had a jacket folded over his arm and we were on a packed metro.

I was travelling with Jorge our guide and 3 brazilian students from the school. Anyway this guy was brushing against me and I am always suspicious but not particularily suspicious as I couldn´t feel anything. My wallet and keys are in my lower right zipped pocket in my shorts. I pushed my bag between us an my right leg and he sorta moved away a bit. But then I knew. My zipper was open about an inch and half. But I could feel my wallet and hopefully my key in there.
Thing is I wasn´t 100% sure my key was there to start. Nor 100% sure that the guy opened it... maybe I didn´t close it all the way. But my gut said he was doing it and then he was with with two other short stocky.

But I did signal to Jorge with a pincher sort of hand motion and pointed to the guy and Jorge acnowledged my signal. But you can´t do much. It´s a packed train and I´m not that fluent in Spanish to be very communicative. By now the pickpocket had moved around towards one of the other students. So I kept my eye on him.

And eventually he moved with his back against the exit doors. At the next station.

He stayed on. But moved from his right pocket to his left pocket a 5 or so inch silver coloured switchblade knife. In my mind, I´m mostly just watching like a hawk. Wondering what I should do and looking for an opportunity to defend or attack. But it was a stalemate.

On the next stop, he and the two others left the train. Jorge assured me that he was a pick pocket. The other students had no clue but had seen the knife.

So from this I notice that it´s a bit of a numbers game and a bit of chess. Three guys possibly with knives moving quietly is a hard to fight threat. Was I willing to risk a knife in the stomach to punch or push a guy? No, unless I had 2 other guys ready to pounce I was at a disadvantage.

Also, it wasn´t a big deal. what I mean is the threat and possibly the description is worse than the whole event. It´s not in his interest to act randomly and say stab me for just watching him. So it´s a game of being careful and defensive. To do it again, I just won´t let anyone near that pocket. And when I have my packpack, put it in it´s internal p0cket.