There has been something right in front of our eyes and yet we didn't see it. (Or if someone noticed it he/she didn't share)

Anyways there has been a scene, a VERY short scene in one of the House promos, were a patient grabbed hold of a brunette woman.
See here: link
(at 0:18)

And this brunette woman I think is Thirteen!!! I saw some pictures of it, where we can see that she is wearing a lab coat and a stethoscope.

Soo, if we look at the newest House spoilers now, which say that there will be an aggressive patient who gets violent with a lady -> it could be this scene! 13 is the lady he attacks.

There was also another new spoiler which could fit:

Apparently JS was on E!News with Kristen, and he said there would be an episode this season involving a hostage situation. Apparently there is a patient who wants a diagnosis, and wants it now.

JS also teased that someone might get killed.

Just speculation, but I'm very excited about it now :D