Riding on a rollout rock into a lava fof instantly kills the player
Lava is solid to players, pass-through for rollout rocks. When you ride a rollout rock into lava, it passes through as expected, but it takes the player with them. The player object then realizes it's inside a solid fof and proceeds to get crushed.
Map is https://mb.srb2.org/addons/srb2-station-v1-2-2-the-place-to-test-your-mods.277/