Should I sign a medical release form to the Insurance company that did not take full liability?

I was hit by a vehicle on my rear right side. The vehicle that hit me Insurance company only wanted to take 50% liability when the police report clearly stated otherwise. I went thru my own insurance company for repairs and did not accept the offer. Now the other insurance company is asking me to sign a medical release form. I did get medical attention which is most likely less than 1000.00. NY is no fault so my insurance company has been handling the bills. I do have a 200.00 deductible. Should I sign the other insurance company medical release form?