Taxying. You may find the following NTSB link useful in developing a way forward.
Access To Data; Privacy, Proprietary and Union Issues
I do not agree with the premise that such data is only to be used in the event of a fatal accident. All data, including CVR data, can provide valuable information and enable error prevention strategies to be identified and adopted. But this requires management and employees to agree the rules of use and it will only work if there is a just culture within the whole organisation.
If there are no such procedures and processes within your organisation then the unfortunate event you have experienced could provide a catalyst for the organisation to develop them for the future. Effective error investigation processes have been implemented in a number of organisations in the UK and the development of these processes are encouraged by both the AAIB and CHIRP