Very much what gnysek said - unless you take measures to verify integrity of code that you are going to run (e.g. use HMAC), this risks unintended side effects.
I would generally recommend TXR for potentially-unsafe code as you get a larger degree of control over what the executed code can or cannot access.
Also, generally it will cause a lot of FPS drop quickly.
Using “live snippets” should show better results than live_call as they were not affected by debug_get_callstack bug (see here).