[quote=@The Grey Dust]
[@VKAllen]

Well the performance might be great acting, they may believe you injured, they might even think you are easier to kill due to your injury. 

I personally think you'd use Deception here in lieu of a Performance + Persuasion/Intimidation check.
Since the PHB (pg 179) has a few listing of what Deception can be used for, and it seems everything your character is attempting to do fits.
Since you'd feign an injury and then convince the guards you aren't a thief, as well as you are on their side.

But it's up to the DM and yourself on how to distribute the rolls :P


[/quote]

Aye! That's what I'm basically doing.