This type of exchange is indicative of a bigger problem.
While I have the utmost respect for our controller colleauges I have noticed a trend ( and particularly in the mentioned country) , where some controllers have a firm grip of the non essentials.
I reckon 90 % of foreign crews ( if the story you relate is correct) would have said ( what the F%^K is Air Med One ?) , and off course the next 10 min spent would be a useless banter between crew and atc ( when we all know what we are trying to achieve)
I guarantee you I can pull out little "notes" like this from every single country's AIP. The question is not one of trying to get things text book perfect and procedurally 100 % correct. Its about solving the problem, often referrred to as the big picture.
If the crew are struggling to understand your "code" and you are worried about litigation or procedure , then just say it in plain English !
" SQ Bla Bla , To give you priority handling for a medical emergency I require you to declare a medical emergency. "
"SQ Bla Bla .Thankyou ( non standard) , we are declaring a medical emergency.
As an Industry we are so busy dotting the (i) and crossing the (t) that no one is reading the sentence !!!