Crucifixion's definitely not the way to go. It's insanely painful. It's insanely prolonged. It's insanely humiliating. It's pretty much just insane. (Those Romans weren't big on clean, quick deaths.)

And it's also super-symbolic.

Because the mention of crucifixion is always tied up with the death of Jesus, and the idea of sacrificing oneself for the greater good. And, in On the Waterfront, Father Barry applies this symbol to Joey and Dugan, who've both been killed by Johnny's mob after word got out that they were planning on turning police informant:

He says:

BARRY: Some people think the Crucifixion only took place on Calvary. They better wise up! Taking Joey Doyle's life to stop him from testifying is a crucifixion. And dropping a sling on Kayo Dugan because he was ready to spill his guts tomorrow, that's a crucifixion. And every time the Mob puts the pressure on a good man, tries to stop him from doing his duty as a citizen, it's a crucifixion. And anybody who sits around and lets it happen, keeps silent about something he knows that happened, shares the guilt of it just as much as the Roman soldier who pierced the flesh of our Lord to see if he was dead... Boys, this is my church! And if you don't think Christ is down here on the waterfront, you've got another guess coming!

According to Barry, what allows these symbolic "crucifixions" to happen isn't just the villains committing them. It's the cowardice and indifference of bystanders. If the other longshoremen followed Joey's lead and turned against Johnny—who hadn't been helping them at all, anyway—Johnny wouldn't have stood a chance.

Terry's act of courage at the movie's end finally shakes everyone out of their cowardice and makes them abandon Johnny together, once and for all. It's just too bad Joey and Dugan had to bite the dust first.