What should you do?

Ok so for you all that dont know I work at WalMart as a cashier/customer service/anything they need me for that day associate. The other day I was running a register when I heard some yelling. I naturally turned around and saw this group of handicapped people and their aides who reguarly come into the store. One of the handicapped girls was standing there and she was wanting something that the aides didnt think that she needed for whatever reason. She continued to scream and yell until one of them told her she needed to go and sit down until they were finished. The aide walked with her over to a bench right across from where I was. Everyone in my line was asking if she was alright because she continued screaming, Give it to me! Well then she started taking off her shoes and the aide told her she needed to put them back on. She got even more angry and threw her shoes across the way where they landed right beside me. I wasnt sure what to do because I was still waiting on a line of customers. So I went to get them but the aide was already en route.
The girl was then guided back to the register where the others were still checking out. She was still upset and began yelling more and then she pushed one of the aides against the register and began hitting her and pinching her. The aide became a little shaken and told the other one that she needed help. The girl then took off walking to the back of the line back to the candy wall of the store which would have been at the end of my line. She sat down and refused to get up but the whole time she was screaming, hitting the aides, and throwing things from the candy wall. Now it is a Saturday in WalMart and if you have been even close to one on that day then you know we are slammed. So everyone was staring at her and asking me and other associates to help her. And I was just lost because I didnt know what to do. I mean I felt terrible but I am not a trained aide and I have no idea anything about this lady or her condition. So what do I do?
Well I turned my light to blinking and told my manager that the aides had asked if we had any security or anything that could help them. Well the only thing that we could do was to get a police officer. So one was called and showed up along with the rescue squad. They finally had to load her onto a stretcher and carry her out.
So my question is what do you do in a situation like that? When you have people who are looking for you to do something that you have no idea what to do? Needless to say we had lots of complaints because "no one" would help her. I still wonder if I should have done something differently, but what?