Wrap your SELECT in an Outer  SELECT LIST(...inner select ...)
try:

SELECT LIST(DIAGNOSE) FROM (
 SELECT MRDIA_.....->MRCID....
 FROM ......
 WHERE .....
 ORDER BY ......
)

What you describe is indeed named Global:
and the syntax could be  ^ehr.IP to follow your question.
It is visible over the whole namespace.
If you use ^%ehr.IP the % makes it available over all namespaces of your installation.

Set ^%ehr.IP="whatever you need" is creating it   
 

@Enrico Parisi :  I fully support your point!
Global mapping - in any form - is the path for CONTROLLED managed growth.
So I wonder about the intention of the "continuation". 

A quite interesting feature.
Did you take a look on how backup management is affected / involved by this design ? 
I just fail to imagine how to keep all this in synch.
e.g. if spread over several drives:
Are they backed up in total or in volume junks ?

Sorry: my typo:   zipcode.csp  generates  csp.zipcode.CLS

<script language="cache" method="AlertUser">  
this generates the method.
But your CSP page works with HTML + js in your Browser
to the Browser that interprets and call just as JS.

BTW: old CSP pages
YES, this hasn't changed since it was fresh ~22 years ago (my 1st training docu @ISC)
and NO browser ever accepted ObjectScript as scripting language.
the <script language="cache"  ...> tag is just a compiler directive and never reaches  the browser.

Principal limit: HTML just knows about JavaScript
JavaScript is executing an XHTML call to your Ensemble carrying along all required credentials.
e.g. sessionid,  encryption, cookies, ....
In your namespace SAMPLES zipcode.cls ia a detailed example,
your call looks like this;

#server(..validateZipCode(zipcode))#

But the generated code is this:

("cspHttpServerMethod")_"('"_(..Encrypt($listbuild($classname()_".validateZipCode"))_$select(%session.UseSessionCookie'=2:"&CSPCHD="_%session.CSPSessionCookie,1:""))_"',zipcode)",!

HTML has no idea about all this

 

OOUHH. Weblink had end of life more than 20 years ago
It was the unloved predecessor of CSP. 

Win authentication is something
IRIS authentication is something else.
They rarely match each other.

Being happy married for 55 years I find the subject of such a calculation just disgusting.

I just would refuse to marry a partner calculating impact of the wedding costs on his retirement.
I'd rather prefer one that attempts to raise his income by working more and harder
and not thinks of forecasting retirement before the wedding.

it's best described in docs

• %DeleteExtent()

classmethod %DeleteExtent(concurrency As %Integer = -1, ByRef deletecount, ByRef instancecount, pInitializeExtent As %Integer = 1, Output errorLog As %Status) as %Status

Delete all instances of this class from its extent. On exit instancecount contains the original number of instances while deletecount contains the number of instances actually deleted.

Internally, %DeleteExtent() iterates over the set of instances in the collection and invokes the %Delete() method.
Refer to Object Concurrency Options for more details on the optional concurrency argument.
The option pInitializeExtent argument allows the user to override the default behavior of calling %KillExtent() when all instances are successfully deleted. %KillExtent() is called by default when the extent is empty so that empty globals can be killed. If %KillExtent() is not called then some empty globals can remain as well as the ID counter if it exists. The default value for pInitializeExtent is 1. Unless the caller specifies a false value for pInitializeExtent the globals used by the extent will be killed. If the process' GlobalKillDisabled flag is enabled and not the default of false the process' GlobalKillDisabled flag will be changed temporarily to false to allow the operation to complete without a possible error. In some cases, the globals used by the extent are not used exclusively by the extent. In those cases it is possible that some globals will still be defined even when pInitializeExtent is true. By default this call to %KillExtent() will not delete default stream storage global, but if you pass '2' in pInitializeExtent and if the entire extent was deleted we will call %KillExtent passing the 'killstreams' flag to ask it to remove kill the default storage global.

Returns a %Status value indicating success or failure.

• %KillExtent()

classmethod %KillExtent(pDirect As %Integer = 1, killstreams As %Boolean = 0) as %Status

%KillExtent performs a physical kill of the extent. No constraints are enforced. This method should not be used in place of %DeleteExtent. Only physical storage occupied by this extent will be killed. If this extent is a subextent of another class then no data is killed. Indexes that originate with this extent will be killed. %KillExtent will be called on any subextents and on any child extents (the extent of the type class of a relationship whose cardinality = children is a 'child' extent) of this extent.
This method is not meant for production applications. It is meant to be a development utility to quickly clear extent physical data. Also this will not remove stream data associated with these instances.
If killstreams is true (default is false) it will also kill the default stream storage global.

You run [IRIS for UNIX (Ubuntu Server LTS for x86-64 Containers) 2024.1 (Build 262U)

when 2024.1 was fresh I had problems because of a processor mismatch and no explicit message related. I bought a new processor to escape this trap.
you may try to check
containers.intersystems.com/intersystems/iris-community:2023.3
that didn't have that problem.
just guessing

GREAT!   forward-compatible

I was waiting for it almost 2 decades!

You started webserver here
04/29/24-15:09:00:014 (14882) 0 [Utility.Event] Private webserver started on 52773

BUT then you ran a Shutdown

04/29/24-15:09:33:048 (15564) 0 [Utility.Event] Shutdown complete
05/08/24-01:34:34:288 (406) 0 [Generic.Event] Global buffer setting requires attention.  Auto-selected 25% of total memory.

and Webserver was NOT started again 9 days later
in fact the whole startup is incomplete.

You may take a look to this old article on a similar case
OR see doku: Restart Webserver
Start/Stop of the container might be the last to try