Purpose of the lever in khudad sewers (spoilers)

[Ojisan]

Theres that small secret area which you enter from alternative entrance inside one of the houses, inside are couple shadow thieve guys few chests and a lever near them.
So i pressed that lever but i couldnt understand what it actually did. Its buggin me since then, what was purpose of that lever

[Forral]

I actually just opens the way back out again. An iron grate dropped down behind you when you entered that area, blocking you inside with the assassins. That lever raises the grate back up again.

[Ojisan]

Bah, and i thought it was opening some secret something hehe.