He made a gesture with one hand as though to say 'there you are'. Because, indeed, there they were. He'd already gathered much of this about Malgus, if not specifically. That bit of confirmation was quite enough for him.

This man was Sith, but he also had a sort of... honor, or at least code by which he lived that while entirely self-serving was not entirely about subjugating others.

Therefore.

"Your key to audience with the Emperor is me. And whatever you can find on the planet were in transit to."

Also why he was going to be dead (probably, though he doubted quickly he was hardly going to rely on Malgus letting him go), but you know what? If it got Palpatine dead shortly thereafter, he'd be happy with the trade.