Sid,
As you must know, I do not fly the EC135 and so have no reason to download the RFM. But every helicopter I have flown (and that's quite a few types, single and twins, including flying in the same police role), requires the engines to be secured in an emergency autorotative landing such as this appears to have been.
If the engines were running or not (I can only assume you mean that in this type they are selected to "Idle", rather than "Off" for an emergency autorotative landing), the Nr would still decay during the landing because they wouldn't respond to collective input, would they?
That was actually my point, not the detail of the cockpit switch selections and a possible explanation of how/why the aircraft appeared to be partly under control but then landed quite heavily, more than would have been expected.
If you wish you to take issue with my post, on this most serious of subjects, as one professional pilot to another, kindly point out my errors in a professional, rather than a belittling or sniping manner, if you can manage that. Especially as many unseen eyes watch this forum. Thankyou.