Soldato
It would use the same electronic timing loops that F1 already has. All you need are 5-7 of those sectors - eg, sector 1 speed reduced, sector 2 constant speed, sector 3 (where the incident is) still constant, sector 4 prepare to go back to racing, sector 5 back up to racing speed. In the incident at question that would cover, what, the bottom of Eau Rouge to the top of the Kemmel Straight at Spa perhaps, with Verstappen's car in the middle, with racing around the rest of the track and no-one gaining an advantage (you would have to ensure that each driver went through the zone the same number of times of course).I don't know if you've spotted that Le Mans is slightly longer than the average F1 track. The slow zones have specific start positions on the entry to corners that could be quite some way before the actual problem and then back to racing speed at the exit of a corner once clear of the problem. You would end up with slow zones that cover a considerable chunk of an F1 track so it makes sense to have a VSC instead.
The only thing that stopped F1 from introducing it is F1.