I recommend the following setup:

use strict;
use threads;
use Thread::Queue;

my $remote_commands= Thread::Queue->new;
my $status= Thread::Queue->new; # responses
sub worker {
    $status->enqueue('Connecting to host');
    require Net::Telnet;
    ... connect to host

    while (defined(my $cmd= $remote_commands->dequeue)) {
        $status->enqueue("Running [$cmd]");
        $telnet->print($cmd);
    };
};

my $worker= threads->new( \&worker );

...

sub btQuery_Click {
    # ... send commands to queue
    $remote_commands->enqueue("cd /");
    $remote_commands->enqueue("echo 'Hello World'");
    ...
};
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