Why don't you study Nuclear physics? vol.2

The man offers me a booze. Passing me a glass of scotch, he continues the words "Young man, you called 'Friend' for the American guy. When did you get to know each other?" I answer that it's 2 hours ago. "Young man, you should not call the person who knew just 2hours ago 'Friend'. Don't believe people so easily. Or you will have a bitter experience some day." It seems like I shouldn't believe even this guy
"By the way, why don't you study Nuclear physics, young man? I went around all over the world like you in my youth. And now, I anchor ports and women all over the world with my cruiser" If it's true, that might be graceful life. But he doesn't look like so rich.

We drunk too much. When he is losing articulation, we kiss the women and leave the bar. I glance my watch. It's 3 o'clock in the morning. He asks me for taking the shoulder. We totter on the sea side street with putting arms on each shoulder. Sea breeze is comfortable for the hot face. "Where are you going back?"I ask him. "To the cruiser" He answers.

Is he really going back to his own cruiser? While thinking about those things, I get to the hotel. I thank him for the scotch. He says "No. It's not big deal. By the way, why don't you study Nuclear physics, young man?" "What do you mean that?" I ask him seriously. However he just smiles and wave his hand "Good night" Although his step is really unsure without my shoulder, he rejects my help and goes off in the direction of yacht harbor. The anger for the illegal taxi has gone away completely.

I had met strange persons in travels. The man who I met at the bar in Valletta is one of them. And I still don't know the words "Why don't you study Nuclear physics?"means.