Yes, you can once Tablo Connect has been enabled on your Tablo DVR and your compatible device has been connected to your Tablo on its home network.
But watching live or recorded programs outside your home uses one of the available tuners to adapt the program to the reduced bandwidth available over the internet.
For a two tuner box, this means that only one other tuner will be available to record a program while you are watching a program outside your home.