Miami, Florida - A dog named Tank was abandoned in the lobby of the Humane Society of Greater Miami. Security cameras caught the heartbreaking moment the pup realized he'd been left behind.

In the heartbreaking clip, posted to TikTok on Friday, a woman walks towards the shelter’s exit before suddenly dropping the dog's leash.

Then, without looking back, the presumed owner slips through the door, leaving the poor pooch behind. The dog, clearly confused, runs to one of the windows and looks after its human.

"Somehow, our front door magnet malfunctioned, allowing him to be left inside," the shelter wrote on TikTok.

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"Thankfully, he didn’t slip back through the door or run away, but he did watch as the person he trusted walked away and drove off," they added.

"Tank was incredibly anxious," the Humane Society of Greater Miami told The Dodo. "He was shaking, frightened, and even urinated out of fear.”

Luckily, shelter workers came to the dog's aid.

After the initial shock of abandonment, shelter workers say Tank has been recovering over the past few weeks: "It's been so rewarding to watch Tank slowly come out of his shell. He's still gaining confidence every day, but the difference is incredible."

They added, "Walks have become much easier, and he's much more comfortable interacting with our staff now that he knows we're here to care for him. Seeing him begin to trust people again has been one of the most rewarding parts of his journey.”

"It’s heartbreaking how Tank’s story began, but we’re determined to make sure that’s not how it ends," the shelter wrote on TikTok.

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The clip went viral with over 170,000 views, and in the comments, TikTokers are asking if Tank is available for adoption.

Tank’s caretakers are optimistic: "His past may have been filled with fear and abandonment, but we’re hoping his future is filled with love, security, and the forever family he has always deserved.”