The unknown switch.

[Firetempest]

After blowing away a pile of spores with a barrel, there is this hack panel. No idea what it activates.

To the left is a spore tentacle that is blocking a grate  to a small chest room that I usually just use a AOE to blow the barrel up just noticed the hole in the paneling in the hallway i can just shoot though. But are these two related?

Edited September 22, 2016 by Firetempest

[Chroia]

Nope. Shoot through the panel in the hall, you blow an explosive barrel wedged into the spore blocking the grate, making it retract.
No idea what that panel does.

[(PSN)Regiampiero]

It opens some sort of door or catapult some where, but I've never seen that particular one. 

[Drakenreiter]

Nope, they're 2 different "puzzles". The air vent is its own thing. To the right of the panel there's a railing and on it a large Corpus crate with what is presumably an Orokin container inside (since it seems to give mods), there's an explosive barrel attached to the back of the crate. You use the panel to make the crate move on the railing and shoot the barrel. You can't wait for it forever however since the railing is broken and the crate will fall into the hole in the middle of that tile.

Edited September 22, 2016 by Drakenreiter