It is not too scary, it has a good set up with the announcement, but there isn't much tension built up after that. Like noises or visual effects that you can add while the player is getting more and more tired.
I really like the announcement implemented, there is a real life fear that can be pulled from this because its from real natural emergency messaging. I don't like that the end screens are still unfinished but I understand that.
You can maybe add some post processing effects like vignette or film grain as the player gets more tired or maybe add some audio that sounds like its on the other side of a wall.