I just saw this nifty video. It explains what that red juice is, the stuff that leaks out of meat.
https://www.youtube.com/watch?v=P8umfq5CNLM&index=18&list=PL674E76450DFCEA0A
https://www.youtube.com/watch?v=P8umfq5CNLM&index=18&list=PL674E76450DFCEA0A