How do I setup nextStage: to be underwater while the first map is on the surface

[The Martian]

I have setup a few new terror missions for the TFTD map pack that have two parts like the Cruise Ship or Cargo Ship missions.

The first map takes place on the surface and the second one is located on the ocean floor.

I've been checking the Ruleset Reference but so far I have not spotted the configuration option for toggling a map between the land and ocean states.

How do I setup the mission so that the map loaded with nextStage: in alienDeployments: is underwater?

[psavola]

FWIW, TWoTS has a mission (LAB) like this. Looking at the ruleset, the first stage has startingCondition: STR_SURFACE and the second has:

   startingCondition: STR_UNDERWATER
    shade: 0
    depth: [0, 0] #Because startingconditions dont work.

Not sure how well this works though. I don't think the engine is designed to work like this, and you can continue using land-based weapons (at least stun grenades) in the second stage (and I doubt the underwater-only  equipment that you didn't get in the first stage will appear on the second stage).

[The Martian]

In that case I'll redesign the maps to be purely land or underwater to try and keep maximum compatibility with vanilla TFTD.

Thank you for the help.