As exhilarating as Luke Lorentzen’s “Midnight Family” is, it isn’t sitting in the back of an ambulance answering emergency calls that will take you aback the most, but rather the question usually asked immediately after the team of EMTs pick up a patient, some variation on “What’s this going to cost?” It’s a concern that usually supercedes whatever pain or trauma they’re feeling, if they’re conscious, and if not, it’s the first question asked by a relative, often followed by what hospital they’ll be taken to out of fear that costs will mount even more. Those in pain are not the only ones keeping a running tally as the EMTs, wary of not getting paid at the end of the night, are keeping track of the bandages, saline solution, and splints used, more afraid of going into the red well after they’ve cleaned the blood off their clothes.

Lorentzen sets up his camera in Mexico City — although you could easily imagine a similar reality across the border — and a simple title card at the start of “Midnight Family” perfectly sums up a nightmarish situation where the government fleet of 45 ambulances is outmatched in a metropolis of nine million people. Private ambulance operators have picked up the slack, but as you slide into the ambulance of the Ochoa family — middle-aged father Fernando, his 17-year-old son Juan and the prepubescent Josue – you see that free enterprise is not an ideal solution for health care as everyone is looking for a cut when there’s an emergency, whether it’s cops who can be bribed to tip off certain ambulances for work in the first place, hospitals who can profit off their services and most grimly, funeral homes when a patient dies.

It’s a horrifying reality to spend any time considering, but extraordinarily compelling to watch, thanks in part to Lorenzen’s kinetic and colorful presentation that conveys the intensity and urgency of every call the Ochoas receive as well as the Ochoas themselves, who clearly have to have business on their mind, but you suspect wouldn’t have gotten into this line of work without genuinely caring about people. Movie stars don’t come more ready made than Juan, the ambitious teen who slicks his hair back every morning for the day to come and far more industrious than his father who rides shotgun, though the younger Josue, who can’t work yet but occasionally be seen poking out in the back of the ambulance is a scene-stealer in his own right. Lorentzen also brilliantly captures Juan’s thoughts at their most unvarnished, whether it’s in calls to an unseen girlfriend or just before he goes to sleep in the back of the ambulance at night where he works through the frenzy of what he just experienced to give him clarity on the absurdity of the situation he finds himself in.

“Midnight Family” channels that madness quite vividly, yielding a constantly riveting film that wrings out every kind of emotion, from anger to laughter to utter bewilderment, from an absurd situation that shows the folly in attaching a cost to helping someone in pain, roaring as loudly onto the screen as the sirens set off upon hearing from dispatch. Answering the call of a far larger crisis than any one emergency, Lorentzen makes “Midnight Family” an unforgettable film.

“Midnight Family” will screen at Sundance on January 28th at 3:30 pm at the Redston Cinema in Park City, January 30th at noon at the Sundance Mountain Resort Screening Room, January 31st at 9:45 pm at the Broadway Centre Cinema in Salt Lake City, and February 1st at 3:30 pm at the Egyptian Theatre in Park City.