In case the test run seems to have stopped or the browser has crashed, it is possible to resume the test run session with the next test after the one that caused the problem by simply going back to http://webapitests2017.ctawave.org:8050. The test runner will recognize the ongoing test session and offer to resume it.
You may start the tests on a first screen (e.g. embedded device) and follow the test progress on a second screen (e.g. mobile device or laptop). Just note down at least the first section (8 characters) of the session token you will be presented on the first screen and enter them on second screen at this location http://webapitests2017.ctawave.org:8050/results.html.