Literally the same millisecond (according to timestamps), or ‘only’ the same tenth of a second or so (as demonstrated by the pictures being near identical)? Those would both be unlikely and remarkable events, but one is 100 times more unlikely than the other :)
Timestamps are not useful for this since the cameras clocks are likely off by more than a millisecond. I think a millisecond is too strong of a claim, but it's almost certainly much less than 1/10th of a second. (a simple though experiment that you could turn into a real experiment if you have a camera: If you take a 1/10th second exposure of something like this the magnitude of the motion blur will be much greater t…
You'd expect in 100 burst of pictures taken like this for one to be taken at the same millisecond.
It's not that unlikely. What's more unlikely is that they selected the same shot and found out about it. This probably happens multiple times every day, just by virtue of the billions of people in the world taking a photo every day.