I just came back from Nikon.
It appears the sensor is OK, but the coverglass ( plastic) has been burnt in.
I effect ; only a sensor replacement is an option to deal with it.
It was a short video - less than 30 sec that caused it... so be aware.
just yesterday i had to deal with an other lasershow.. ( they are popular)
I noticed that the laser was not able to shine directly into the eyes of the audience. But because i was the only one on the balcony that position could be effected.
So that is an additional reason why it happened, and could happen again.