In Chapter V, after Juana tries to rid her family of the pearl, believing that it has brought evil upon them, Kino reacts viciously toward her, knocking her down and hissing at her like a snake. After she drags herself up, Juana remembers that when Kino was previously attacked, he said, "I am a man."
...and that meant certain things to Juana. It meant that Kino was half insane and half god. It meant that Kino would drive his strength against a mountain and plunge his strength against the sea....and Juana had need of a man; she could not live without a man....Of course she would follow him, there was no question of that.
Therefore, after Kino--"half insane"--kills a man when he is attacked in the night, he suggests that Juana and the baby hide because the trackers are after him because he can pull these evil men away from her and the baby and because he can move more quickly without them. Nevertheless, Juana, who has a strong sense of family, refuses to go; moreover, she feels too vulnerable without a man; so, because she cannot survive without him, she is willing to risk danger in order to keep her family together.