Factual error: Bryan's hot wiring of the Volkswagen Golf is feasible, all except that he doesn't break the physical steering lock that would prevent him from turning the wheel. Old Volkswagens are quite difficult to break the steering lock, a sharp snap of the wheel does not break it as it's quite a bit more sturdy than a mere pin. Pulling at the wires does nothing to affect the steering lock, and the lock is shielded precisely to stop outside tampering. Not enough time had passed for him to achieve the task of removing the security. The scene shown is not a condensed montage scene, it's a complete scene from start to finish of what Bryan did to steal the car, and the steering lock was never broken.
Factual error: The weapon Bryan uses to kill the Albanian kidnappers is a Beretta 92FS (M9); it has a 15 round magazine, yet he fires 17 times without reloading.
Answer: Actually, what Bryan Mills did was perfectly possible. He strapped a mobile phone to the two way radio, and used the other two way radio to talk. By speaking into his radio, it transmitted it to the other radio, where the mobile speaker could hear and transmit his voice. The French police would have been able to triangulate the source of the mobile phone signal from the particular 'cell' (i.e. area) that the mobile was using - while that would lead them to the phone position, he'd be elsewhere talking on the other half of the radio.
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