Testing indeed - And for what purpose???
Night HEMS is already well established in the US, and the safety record is abysmal.
Here in the UK, 80% of the landmass is within 30 minutes ground ambulance time from a hospital (and lots much closer than that). Areas without short travel time to a hospital tend to be remote hostile terrain such as the Highlands, Snowdonia, Yorkshire Dales etc where single pilot NVG is probably a bad idea anyhow. Leave that sort of thing to the Military.
Hospital transfers perhaps have more merit