Yeah in the movies anything is possible. They had a concentrated microwave emitter in the first film, which was not real. Liquid nitrogen has great properties, he could freeze entire walls and break through them with nitrogen(to rip off banks, it can freeze metal not made for extreme freezing temps, ex. steel and so on, but titanium can hold up to it, just becoming extremely cold). The problem with liquid nitrogen is that if he freezes bruce he will most likely die.
Personally It would make a lot of sense if he was albino(having red eyes, with little vision, or hair). He could also have a birth condition in which he requires cold dry air.
I would rather he be completely obsessed with a girl he treated while he was still an M.D., she developed cancer which brought on heart failure, so he cryogenically froze her, preserving his great love(they were never married), until he could cure her. When the medical board finally found out what he had done, they sh** canned him and sent police after him. He only had liquid nitrogen on site, so he used it to kill the officers(knowing they would send him to jail and take away his love). His constant exposure to liquid nitrogen burns his skin causing near death. He uses the rest of his money(that he obtained over a long career as a doctor)to build a suit in which to work in this environment(with titanium and other non freezing materials). He builds a gun similar to a flamethrower, but it sprays something that he has an abundance of liquid nitrogen. He needs money to continue his research, so he hires a bunch of nobody bank robbers and begins robbing banks and taking money(killing the men as he believes they are a hinderance to society, he is extremely vain, believing himself smarter than everyone as well). He does not want to kill batman, but if he gets in his way, he will do what is necessary. In the end he would kill everyone in gotham if it meant saving his love.
and there are mini liquid nitro guns, like torch size or spray can size.
