Just because you're in a DMZ doesn't mean you can't sent it. It simply means your network admin is restricting you to have access to your SMTP server. Pretty simple to poke a hole for that server to request that acces.

In regards to your confusion, yes that method will send the email but what I was getting at is the functionality before that particular method. The functioality before that method shows you how to get an email template, resolve macros and assign the values to other objects, in this case a Kentico Email object. You could simply take the email template info and assign its properties to any string you want. For instance if you wanted to display the message on a page, simply take the results of the eti.Subject and assign it to a label or whatever control you have on the page.