A direct connection from a branch circuit panelboard ground bus to a reference ground bus does not meet the patient care vicinity requirements of NEC 517.14.
Article 517.14 [Panelboard Bonding] of the National Electrical Code (NEC) is one of the unique requirements for a health care facility. It’s been in the NEC for quite a while — at least for the duration of my career. This Article is intended to addresses the risk of creating a potential difference between panelboards that could put a patient at risk for electric shock. Most health care facilities are served by multiple branches of power, and the Code is pretty clear regarding what branch and how many sources of each branch are required (or allowed) in patient care areas.