I am so sorry to hear that you have had such a difficult situation at your former job. Washington State does have a whistleblower statute that may apply to your situation. According to the Washington State Human Resources Commission website:
"SB 6776 gives more protections to whistleblowers and employees who allege whistleblower retaliation within state government and higher education institutions. The State Auditor’s Office (SAO) enforces the whistleblower aspects of the law. To file a whistleblower complaint, you can contact the State Auditor’s Office or an agency designee, as defined in RCW 42.40. More information about SAO can be found online at www.sao.wa.gov."
You may wish to contact Washington State attorney who has experience in such matters.
Also, if you know that a nurse has been doing something that would put patient safety at risk, you might want to contact the board of nursing.
Good luck in resolving your retaliation claim.
Usually any time of severance agreement would contain a provision in favor of the employer that the amount being paid resolves ALL issues whether known or re-litigating this matter. You should have the agreement scrutinized by an attorney whose practice focuses upon employment law.
This answer is predicated on the facts provided in which the lawyer cannot confirm or verify. I do not represent you as we do not have an attorney-client relationship until a fee agreement is signed by you and me. I am licensed in Washington State and California. Beverly Grant Law Firm, P.S.
Any severance agreement is likely to have waivers of all claims. In California, workers compensation claims cannot be waived; I don't know if a rule like that applies in Washington. I have published a legal guide on the subject of severance agreements that you might find helpful; I've added a link below.
This response creates no attorney client relationship; consult a local lawyer for help if you proceed.