I'd assume the help from the Empire came with strings attached (dude mentioned plans they should be working on going forward even with everyone poisoned already), so she rushed her plans and didn't stop to think they were using her differently than they openly told her they were. Like, if you tell someone you're going to exploit them for resources in less fair trades from now on, but you'll give them everything they wanted in return, they aren't going to really expect a double cross because they were already getting a shit deal.