An even Darker SOMA [ending spoilers]

[Noble81]

The WAU was not on the ark! I won't/don't believe it

If you look at the ark and the space gun neither are visually effected by the WAU. Everything else in the game that the WAU has affected has that look to it, you can tell it is infected.

In the room you first pick up the ark there is WAU in there but it has not infected the woman and it has not touched the ark...

Oh and I took Catherine turning off not as the WAU terminating it but that the virus was working at all systems were shutting down.