My problem happens after taking the elevator away from the (exploding) Tetra factory.
When I meet Jenna and get caught by the red dude, the screen turns black, as a a KO effect. Until then, all normal.
The problem is that the screen stays black after sereral minutes, several hours later and nothing changes. The game didn't freeze, as I can use the Esc button to open and close the Pause menu.

What can I do to solve this?

As a hint, I used the trick posted here on the forums to bypass the death error with the polebar (when you cross an acid pit just to die when you just arrived); wait for the crates to fall and, then, keep moving.

I've played the game many times, but never had that particular problem. Sorry.

Nevermind.
I was able to solve it on my own.

For those who MAY have the same problem in the future, this is what I did:

The key was to take EVERY medipack on the tetra mission.
Then, if that doesn't work, try to press Enter as a way to speed up the cutscene.

Thanks anyway for the intention, gcruse. You were the only one who answered me in weeks.