Loki secured his freedom from capture by using a clever deception involving the use of his shape-shifting abilities. He tricked his captors by transforming into a female horse and subsequently mating with another horse, leading to the birth of sleipnir, an eight-legged steed. This ploy not only showcases Loki's cunning nature and resourcefulness but also reflects themes of transformation and identity in Norse mythology. His actions contributed to his complex character as a trickster, embodying both chaos and creativity within the mythos.