Chiller outfits let you 'fly' underwater, as do frogman suits for peasants or males. The benefit of both of these is that you don't need extra oxygen either.
Still if there isnt an entrance on that lower left side then there's no
Regular entrance to even get to the 2nd stage of the mission,
and there's nothing in the mission description to suggest thats a problem. In fact a "tunnel" suggests it goes DOWN and that it will be recessed into the ground tiles 2 or 3 floors down much like the infested cellars. Im looking for a hole.
I suspect that Brick also has a 10 spot spawner for that deep one as a goalie, making sure you have to get in there to kill all enemies.
(I was running heavily armed, air muskets with WP ammo, and 5 Minilaunchers with a bunch of Fire Minibombs)
Overall, bad design.
Id also wonder what the point is just to get a dil.do since they dont really do much and you get plenty from ratman caches. I figure there should be magic gear items there, something actually worth something. I mean it could just be a lesson that some missions just suck and you just ignore that kind after you get burned with it.
I mean NOW that I know its possible to 'fly' underwater and its built into that map as a requirement (hey what about the 1-3 gals who cant 'fly' and reach the exit tiles?)... well I can plan for it.
But Now having played it I know its NOT worth even going there, so there's not going to be a 2nd try because its pointless. At least in Sunken Ships you can find Shadow Orbs. Id go for it if there were Dark Ones with UAC Plasma Rifles for me to snatch, or a big steaming pile of Aqua Plastics.
Abit like the Space Freighter, after I stunlevel'd everyone I noticed just how nasty some of those critters might've been... I actually might not have been able to handle those Droids and even with boom guns im not sure if the Ship Officers could be taken down (red shields). There were bodyguard armor parts there but the only other benefit was a Damaged Syn on the ship.
Yeah well, you find Damaged Syns in some of the regular Orbital Missions too and zorching a few guild guys in 0-G is a heck of alot easier. Thats where I remember getting like 5 Syn Gals overall in a previous playthrough. I haven't hit that type of orbital derelict ship in this playthrough yet.
Thats all speculative or opinion though. There is still a Bug there. And there are serious bugs with everything else I described.
Also No Exit Grid is a big problem no matter what kind of map it is. Because that means reloading a Geo save to get out of it.