The Incident (2017)

Two brothers are running from a shooter in a stairwell when an explosion happens, which seems to trap them in an endless area loop. Though supplies regenerate with regularity, they continue to age. Similarly, a family sets off on a road trip -- hears an explosion -- and suddenly their area becomes the ONLY area.

There's some bullshit explanation at the end of the movie about this being an alternate timeline generating power from which the actual people in the actual timeline will benefit, but it's convoluted and tedious.

D