doogald is right, there's no way to buy a Turbo 2 without activating a line on Verizon. If you do that and cancel the line after a month and pay full price for the phone though, it will support some of T-Mobile's LTE bands. They use bands 2, 4, and 12, and the Turbo 2 only lacks band 12. Since 12 is their 700Mhz spectrum band which penetrates concrete and buildings better, my guess is your LTE coverage will vary depending on where you live and how much time you spend inside signal-blocking buildings.
Your other option is to source a Moto X Force from another country since it has all of T-Mobile's bands, but you'll pay a premium for it. The Turbo 2 starts at $624, and you'll need to pony up at least $900 to import an X Force from elsewhere.