Another way for you to know what you're thinking

wouldn't that result in a endless loop?

pointing a camera at a tv

You're thinking about a brick wall.

Would probably see whatever focusing is required for mind reading. Also some versions of the idea of mind reading don't make it so you have to focus so hard you can't hardly think. With a lot of shows and such it's just something that happens. They can flip a switch and it's either on or off. In that case you'd just be reading their reactions to your thoughts

It's would be the white noise of a TV but louder and louder like a microphone in front of a speaker until they stop or one dies. But that's only if they're reading what the other is currently thinking consciously