Watching these kinds of videos of the worst case scenarios of rodent problems won`t help you. You're lucky to have a cat because rodents tend to stay away if you have a cat and/or dog in your home. Probably why it's staying in the walls for now. I do have a few suggestions to help you in this.
First, I suggest not using the poison at all for the safety of your pet.
Second, I personally use kill traps when I find a mouse in my house, but they do have non-kill traps that work too. However, that means you have to get rid of live rodents yourself.
Third, this one is an old farmers trick my grandfather taught me is to use cheap bubble gum and let them eat it. Mice and rats tend to gorge themselves when they eat and the bubble gum won't break down in their stomachs and it also expands to burst their insides.
Worst that could happen is that your landlord needs an exterminator, but I doubt it will go that far.
Hope this helps.
We are all insane, we just act normal for the sake of others.