groupActivityOf fails with fast events (or something)

**Shared Program**: https://code.world/haskell#PySpd_fhz7PMTpiViNhV1Fg

**Description**

I was trying to write a freeze tag game played by several players. Unfortunately only the movements of the player 0 actually propagate. Movements of player 1 register in a trace, but even when only one player is moving, player 0 sees traces from both players as if they are both moving. I do not know the architecture of multiplayer activities, but it seems like player 0 acts as a server for the other players and that is failing to apply movements from other players and propagate them correctly.