Except if this vulnerability is real (I phrase it this way because people are questioning the legitimacy of this hack), then the malicious page circumvents that sandbox you're so ready to hide behind as well as other security features, all without crashing the browser or otherwise immediately alerting the user. You wouldn't HAVE the chance to close the tab since if you would find out after it was too late.insect said:
Run in a sandbox and who cares if a script tries something malicious. Just close the sandbox instance (i.e., tab).
Just sayin'.