Violence towards staff and mgmt response

I need to vent but i also want to pose a question.

today, i had a six year old psych patient who threw a tantrum on the unit. This kid functions at the level of a 18 month old, so the tantrum i can handle. he then started slamming doors, i intervened because i did not want him to chop his fingers off. the tantrum then grew more violent and he bit me. i did not medicate him because he really is not able to understand his actions as well as someone who is all there. i just wrote up an injury report and moved on.

Later in the day, i had another kid (17 year old) who got angry because the doctor would not increase her meds. She threw chairs and overturned a table and finally punched a nurse in the eye.

At this point, i had the nurse who was assaulted call the police to file an assault report. they came on to the unit, did their due diligence and finally decided to arrest her. she was led off in handcuff. The problem is that the patient advocate was angry with the police for doing this as well as being upset at the nurses for calling the them. she was demanded we implement a process for going through administration before we call the police.

now my questions are (keeping in mind i work at a state hospital in texas)

1. what right does she have to trump my right to file a report of assault?
2. has anyone had this problem before?
3. just because i do a job as a nurse does not mean i will allow myself or staff to be assaulted, am i out of line for thinking this?