When Boston Globe arts reporter Geoff Edgers and multimedia producer Darren Durlach proposed making a documentary about five runners who were crossing the Boston Marathon finish line at the moment that the bombings took place, editor Brian McGrory’s reaction was: Why not?

“What do you need? Two weeks?” McGrory recalled asking them.

As it turned out, it took Edgers and Durlach eight months, thousands of miles on the road and, as McGrory put it, “God knows how many dollars” to make “5 Runners,” which premiered before a crowd of several hundred people at the JFK Library Thursday evening.

The 25-minute film, which McGrory called “the first full-fledged documentary that the Boston Globe has ever produced,” will debut on NESN on Monday. It’s an early sign that a strategy to move into television, which Globe owner John Henry announced earlier this year, is beginning to take shape — although Edgers and Durlach began working on the film before Henry bought the paper. (Henry is also the principal owner of the Red Sox, which controls a chunk of NESN.)