The play received 'mixed' reviews. = The play's reviews were 'mixed'. [=some critics liked the play, while other critics did not]
I accidentally 'mixed up' the two files. [=I put each of the files in the place where the other one should have gone]
He 'got mixed up in' a plan to destroy the government. [=he became involved in a plan to destroy the government]
(..) And they weren't what she was after. - What was she after? - My fingerprints. It was printer toner mixed with graphite on the safe. It gives a good pull and it's untraceable. Fascinating. You two should exchange notes over coffee. So, now you're tryin' (..)2012 The Dark Knight Rises