but, as Battletech TT has rules for fighting underwater, I see no reason,
not to have an underwater map but hopefully it will eb a situation, where you know beforehand that you´ll fight underwater maps...
after all there are restrictions (LRM/SRM only in their Torpedo version, Ballistic Weapons IIRC functionless, Lasers etc. with reduced range) and I assume, not even a social general will send his mechs on an underwater mission, without in forming them beforehand, so they can prepare
The water level was the one where you were in a Executioner/Gladiator with some torpedoes
and PPCs. The level I can't beat ( SPOILER ALERT! ) is the last one where you jump from one space ship to another and blow it up from the inside, then escape from.