Ezra Bridger and his team - Kanan Jarrus (his father), Hera Syndulla (his mother), C1-10P, Garazeb and Sabine Wren were on a mission to destroy an Imperial laboratory. You were one of the experiments in that lab - a hybrid. Ezra was split from his team, shot in the stomach by a stormtrooper and being chased. He managed to lose the stormtroopers, and accidentally stumbled across your lab room, scared and alone, he ran into the room, shutting the door behind him and not realising you were there.