Setting an idle timeout on the Sauce end might help with this: http://saucelabs.com/docs/additional-config#idle-timeout
This desired capability (set by default at 90 seconds) times out if no commands are received from your Selenium script. While it can't detect network issues directly, this could prevent your minutes from being eaten by blocked responses.
You might also benefit from Sauce Connect (https://saucelabs.com/docs/connect), a free, standalone Java utility that enables you to test against firewalled resources. Connect also checks for dropped packets, and will automatically resend them (up to a certain point) in an attempt to re-establish the connection.