It doesn't sound anything like the lion is stalking anything. It simply has a point source of food in a restricted area and is trying to take advantage of it.
Let's see, man with soft underbelly all over, not real fast on two legs and tortoise slow on all fours (compared to a mountain lion), no claws, short and blunt teeth, relative poor sense of smell, fair hearing, armed with a pellet gun versus a large predator with big teeth, big claws, very strong for size and very strong compared to most humans, covered in fur, very fast, extremely skilled, kills and eats for a living and so is highly motivated, and much better senses of smell and hearing....
My money is on the lion.
"If you look through your scope and see your shoe, aim higher."
-- said to me by my 11 year old daughter before going out for hogs 8/13/2011