How to Archive a Site as a Sub Site

I'm having a tough time cracking this and need some assistance. Below is a site called TestSite, that is used to archive other sites not in use located at contoso.com/sites/Prong2/JRS/testsite/default.aspx:

I want to archive a site called Sporting Goods as a subsite that will be located at the Sites and Workspaces section along with the subsite Archive Test shown below:

I am familiar with the Powershell cmdlets to export and import a site but I came across a problem I need assistance with. For some reason when I export a site, the site that I exported is still available in the original location that it was from. My understanding is when I export a site using Powershell that it would remove the site from its original location. Can someone clarify why it isn't so? Lastly, is there a cmdlet I can use to archive a site as a subsite? Any assistance would be appreciated.