Old Note Found on Corpse

[Seems to be from a companion who came along]

Can you believe that key I found belongs to the Blades?
I was going to return it for a reward...

But those bastard Blades would never be so generous.
We'd be better off sneaking in and grabbing things for ourselves.
What do you say? It's a perfect plan.
Come to the outpost. If you're late we'll go without you.