Kongpob was immediately taken by that P. I mean come on, it's very rare, that someone approaches a random stranger, talk to him, help him, share his personal experience, and indirectly, make him choose something which he was surely gonna reject.
And to top it off, he even gave Kongpob a cool drink to soothe his anxious nerves.
Who does that?
So Kongpob can't be blamed for falling for his P, and out of his love for him, pursue engineering, right?