What you are doing makes absolutely no sense.
//scid $cid <command>
is the same as doing
//command
You are setting the connection to the id of the current connection, and then performing a command. Think about how that sounds for a while.
To illustrate try in any server window: //scid $cid echo -s hello
Guess in which server window's status window it will echo that...(-a is different, because of it's special feature of echoing things to your active window, whichever server that migth be)
Also note that you are setting a bad example with executing commands directly in a /scid command. Preferable is to use:
scid <N>
command
This isn't gonna go anywhere without taking the time to try to understand how multi-server works, all you need to do is type /help /scid, read it a couple of times, think, read some more, test, think and that should be it.
Additionally, take a look at
$findcid() and the code examples that are included in the top of the file. They will help you understand the multi-server feature in mIRC a little more.
