So my question being. . . . we had a cordless phone in there, but I was afraid if they heard me calling the police, they'd flip out and run in or if they heard us moving (like if we moved to the closet before calling) and hurt us. What should we have done? Eventually I ended up quietly grabbing the squirt bottle we use on the cats (we have NOTHING of defense in there, and I thought that could at least stun them if I sprayed it directly into their eyes) and sneakpeaking into the room where the noise was coming from, and everything was in order. And then I carefully looked through the rest of the apartment, and it was all in order. . . . and all locks were still on, perfectly in place, nothing broken through and everything. Even all the windows were locked.
I think it was one of the cats doing something weird in the litter box, from how the box sounded when I accidentally kicked it, but I've NEVER heard it sound like that before.
Now I'm kinda glad I didn't call, becuas eI would've looked like a moron.