Complex sentence: The team's raid on the tunnel allows Alejandro to sneak through to the Mexican side; once there, he kidnaps one of Díaz's mules, a corrupt Mexican police officer named Silvio.
Split into simpler sentences: The team's raid on the tunnel allows Alejandro to sneak through to the Mexican side. Once there, he kidnaps one of Díaz's mules, a corrupt Mexican police officer named Silvio.