Chrissy Lee Polis was the elderly woman to tried to intervene and was punched in the face by one of the black women. She is not the woman being severely beaten in the video. I have heard this a few times and it seems odd go here for the arrest report PDF
http://www.baltimoresun.com/media/acrobat/2011-04/61087659.pdf
first page of report it states cut to mouth/face condition Fair, name is redacted. Scroll down to page two and you find the name Chriisy Polis at the top of the page it states Redness around right eye condition/good Declined to file charges , now to me they are clearly talking about two different people if not why the different injurys from page one to two?
Also note that in all reports the older lady who stepped in and tried to stop the fight which is shown clearly in the video all reports it is stated she was hit in the face or eye depends on what and were you read.
I would read that report as showing CLP to be the main victim, not the witness.