Sorry sir i didn’t correctly explain my point.
Here’s what I mean: A human who seems normal may be on the verge of becoming a paccekabuddha. Like you said sir, about the paramis each of us pratice them at various level. To becomes a paccekabuddha one need to pratice for two incalculables (asankeyyas) and one hundred thousand kalpas the 10 paramis. This kind of person leaves from the puthujunas stage to the arahant stage, directly, without having to go through the other levels of the magga phala. I remember a sutta where Lord Gautama Buddha told several stories. Among these stories was that of people who became paccekabuddhas upon realizing their misdeeds. One of these people was lusting after someone’s wife. Realizing that he was generating unhealthy thoughts, he practiced anapanasati (the real not the mundane) unconsciously. This person saw his householder attributes disappear and became a paccekabuddha.
I will try to find this sutta !
(Here is my personal opinion I could be wrong of course: It seems that many of these paccekabuddhas and regulars arahants did not even know that they were going to attain Nibbāna. As you said sir Lal arahant Santati is an example. Nothing foreshadowed that he was going to become arahants!! A few days before meeting Lord Buddha, he was fully invested in kama ragā!!