Now that you've read the script in class and seen the film with subtitles, you should have a pretty good idea about each character's traits. To find precise language from a character, search through the scripts for the direct quote.
Command + F is your friend. (think f for "find") It's a pretty universal keystroke you can use on websites, pdfs, email, most applications. A small box will open– usually near the top of the page which you can type a keyword into (perhaps "knife", or "Juror #2", or "reasonable doubt")