here is my interpretation:

vars Close; // unintialized vars GLOBAL

function run()
{
Close = series(priceClose()); // series that generate within run()
}

the way this would work is the series is running within run() but sends the series data over to a global vars.
But what is the outcome of " the pointer expires every time run() is invoked."?

Does it mean Close is only capable of accessing [0] since the pointer is expired each iteration of run() ?