I genuinely dislike these smooth-talking narcissistic psychopaths. They're like the guy who pushes in front of you in a long line and offers a charming but false explanation. Great for him but everybody else is deprived of the place in line that they've earned. Very amusing to see DeMara in all these high-status positions -- doctor, researcher from Yale, prison warden, monk. Suppose he'd killed someone on the Canadian destroyer? It doesn't help that he looks heavenward and mutters, "God, please don't let me kill anybody." He should have thought of that before. And his settling down with a straightforward love of his life who reforms him is unbelievable.
That gets the bad stuff out of the way. Tony Curtis is near his best, jaunty when it's called for, sweaty and nervous when necessary. His meeting with Mickey Kellin in the dark prison cell is pretty spooky. We can believe that Curtis is scared. We can also believe that Kellin is anxious to cooperate in some scheme that saves both his neck and his face.
The scene in which Curtis, as a Canadian doctor must remove the abcessed tooth of Captain Edmund O'Brien could not be improved upon. I can't watch that scene without busting up. O'Brien frozen in this awkward position, an agonized expression on his face, like an exhibit in Madam Toussaud's Wax Works.
I'm glad he finally got caught before he caused too much damage. Speaking of the damage we don't see much of it here. It's all pretty lighthearted, which is one way of approaching exploitation. An example of what I mean by "damage." I would feel sorry for the Naval officer who falls in love with him and redeems him, if she existed. In real life, these stimulus-hungry anti-social personalities are easily bored. They tend to attract women, use them, and blow them off. I would expect DeMara to have left a lot of hurt women along his madcap trail.