About halfway through “Safe Place,” a film already not given to taking it easy on viewers’ emotions, the meek, honest delivery of a single word — “Sorry” — shatters the heart irreparably into a million small shards. It comes from Damir (Goran Marković), a quiet, bearish but child-eyed man who has just attempted to take his own life. His stunned, protective brother Bruno (Juraj Lerotić) won’t hear of any such apologies, but still that plaintive “sorry” hangs between them, perhaps standing in for several unexplained factors from the past, perhaps covering further devastations to come. Every small word and gesture counts for a lot in Croatian multihyphenate Lerotić’s sparse, still, tender-as-a-bruise debut feature: Any bigger ones might throw a severely delicate situation off-balance.

Ordinarily, one would advise a first-time writer-director not to further burden themselves with a leading onscreen role in their freshman effort, least of all if they’re not a seasoned actor themselves. But the rules for Lerotić — graduating to features 12 years after his short “Then I See Tanja” racked up some festival miles — are perhaps a little different. With “Safe Place” drawing directly on his own pained family history, and the director effectively playing himself in this autobiographical work, it’s easy to see why one might find a certain security in taking as hands-on an approach as possible to such fragile material. Either way, the gamble has paid off: Fresh from winning three awards at Locarno, including the best first feature prize, the film now appears in the main competition at Sarajevo, with a long trail of further festival bookings surely ahead. Interest from discerning distributors, too, should raise the profile of “Safe Place” far above what is standard for Croatian cinema.

Not content simply for abundant surges of feeling to carry his story across the line, Lerotić also tells it with remarkable formal rigor and economy — evident from his and DP Marko Brdar’s exquisitely lit and composed establishing shot, which calmly takes in the everyday comings and goings of a drab Zagreb apartment building, before our eye is drawn to a man attempting to subvert the intercom entry system, his panic perceptible even in dusky long shot. It’s Bruno, agitated after an alarming phone call from Damir. After breaking down the doors both to the building and to Damir’s pad, his fears prove justified, as blood from his brother’s self-inflicted wounds smears the walls. Damir is swiftly hospitalized; a bewildered Bruno is charged with answering startlingly unsympathetic questions from police and medical staff, when all he has is a surfeit of unresolved whys for his brother.

While keeping the focus squarely and intimately on the family, Lerotić’s lean script draws some darkly comic blood from the inefficiencies and insensitivities of bureaucracy in response to such moments of acute personal crisis — there’s a vein of mordant procedural satire that sets this otherwise universally resonant story firmly in a tradition of Balkan and Eastern European filmmaking. It’s that callousness from above that spurs Bruno and his mother (Snježana Sinovčić Šiškov) to make the hasty and possibly ill-considered decision to move Damir to the family home in Split, where the patient takes a turn for the worse, further endangering himself.

By this point, however, this hitherto serenely naturalistic exercise has already pulled off one deft, disorienting reality tilt. It’s a theatrical flourish that Lerotić and editor Marko Ferković execute with deceptive, uninterrupted restraint, and a fillip between life and death that, though proceedings quickly switch back to the film’s established world, thereafter places the brothers’ tensely loving relationship on a fractured, uncertain footing. Brdar’s elegant, precise framing frequently forces us to observe their interactions through open but obscuring doorways and windows that slice off slivers of their figures and expressions: Even when we share the room with them, deep pools of melting shadow can distance us from the full picture.

“Safe Place” offers scant details about the principals’ lives, loves or livelihoods outside this immediate present-tense tragedy, but the performances tacitly fill in a number of blank spaces. Marković, who deservedly won best actor in Locarno’s Cineasti del Presente competition, is quite astonishing as the infinitely wounded Damir, whose spare, strained, frequently whisper-soft dialogue reveals less of his torment than his sorrowful faraway gaze, his slow, clenched body language and his almost infant-like air of obligation to his brother. Bruno and his mother insist that Damir showed no signs of depression prior to a recent patch of “low spirits,” but as played with such bone-deep sadness by Marković, that hardly seems possible. “Safe Place” invites its audience to consider how intuitive we are to the pain of those we hold closest, how attentively we’re listening past what we like to hear, how safe we’re actually making the private places we share.