Yes. I asked an acquaintance from Manitoba hydro about it. this is what he wrote.
My dept. has had numerous discussions about this very same video.
They are using a device called a circuit switcher - it consists of an air-break mechanism and vacuum chamber (vac-rupter) that is used to break/extinguish the arc under load. If I recall correctly, this cct. switcher had it's vacuum chambers fail and lose vacuum, thus severely de-rating it's interrupting capacity, they called on it to operate and break load - which it didn't really succeed in doing.
If you notice in the video, a bit closer to the camera is the 500 kv O/H buswork, if there had been a wind (or a different wind direction, for that matter), the arc would certainly have drifted into the buswork (or into the other 2 un-failed phases of the circuit switcher) and caused a 3 phase flash over with no means at all to extinguish the arc, other than the over current relays acting on the fault that would ensue when the whole structure fell, or possibly the harmonic units sensing some really ugly stuff and tripping the line via an upstream breaker.
I happen to have a sister unit to the very same circuit switcher in the video installed in one of our export stations, we use it to switch a 200 MVAR reactor bank for power factor correction, the other end of the export line I'm talking of, has the same cct switcher as well, but they use it to do the opposite - they switch in/out a 200 MVAR capacitor bank.