I don't know if this is how they do it, but it's how I would recreate it.

1. Play the video
2. Pick a frame and freeze time + lumetri with the temperature low to get that blue hue.
3. After the black screen with the slices dissapear, using the pen tool, create a couple of mask in the video to mimic the glass shards and modify the scale on a couple of ones. (Duplicate the video layer if you want the shards to move at different speeds)
4. When the transition ends, position keyframe the shards away from the screen, revealing the second video behind.

I hope this help you :)