Momentarily isn't 30 seconds, or even two seconds. Flashing your landing lights is like changing the radio station in your car to one of the other preset stations. It really is momentary. If you want to suggest that maybe he missed the first half second of the fireball, maybe it could be the case; but it's certainly not the impression I got from him; and it's not relevant either.
ML/NJ
I said momentarily. All good pilots do that. And all good drivers glance at their radio momentarily to make sure they're changing to the preset station they want.