The many crucifixions outside Jerusalem come with several layers of this.
First, crucifixion was a big deal even for the Romans. It was typically applied to slaves, bad criminals, or especially noted enemies of the empire, and it was actually forbidden to higher-status Romans because of how bad it was. You didn't just die, you were displayed naked, you were left to rot so you couldn't have an honorable burial, a bigger deal in Roman and Jewish cultures. And unlike Jesus's crucifixion, which is described as lasting a day or less, a typical crucifixion lasted multiple days, as you slowly died from a mix of pain, discomfort, and simple dehydration. The fact that the campaign is severe enough that they're crucifying so much is a sign that the Romans are going scorched earth on this one.
Two, historical records note that a typical crucifixion would have guards watching it to make sure friends of the victim wouldn't just pull them down and recover them, as Josephus had done with some of his own friends. But the numbers are too great for them to be guarded, so it's conceivable that the Jews could sally forth from the city and retrieve people, right? Except that the Romans probably don't take bodies down until they're replacing them with a fresh victim. Any empty cross they found would be a sign that enemies had been nearby. The crosses aren't just intimidation, they're a gross surveillance system.
Three, the good guys have to travel through the crosses, and for the above-mentioned reasons and others, they can't save any of the men. Imagine traveling back in time and that getting to be part of your experience.
