Even if (for now) it concerns land vehicles only, the point about delaying assistance is still valid.
Two thoughts about it:
a) from the HSE drone's point of view, he should know that you can argue that the risk posed by a delayed response is more serious than that posed by not completing an HSA, and therefore that's what he should have written in their HSE management plan.
b) from the responders' point of view, surely they will have a stack of pre-filled forms which only require a quick signature before launch, either that or they'll have the sense to leave someone at the station in charge of filling the thing in.
And that's all from me. I worked as an EMT for a short while in a former life--luckily it was in a land where we were given ample freedom of action and the courts, society, and government were (and I believe still are) very supportive of our role.