Google’s self-driving car unit, Waymo, pursued arbitration against one of its star engineers last fall before filing a lawsuit in February against his current employer, Uber, for theft of trade secrets.

Waymo claims that its former employee Anthony Levandowski stole 14,000 confidential documents before leaving to start the self-driving truck company Otto, which was acquired by Uber shortly after emerging from stealth. Waymo also claims that Uber and Levandowski copied its designs for its LiDAR sensors, a core feature of its self-driving technology.

Uber’s lawyers have been pushing back on the claims over the past several weeks, questioning why Waymo isn’t suing Levandowski instead and saying that the most salacious claims of the lawsuit should be moot based on the binding arbitration clauses in Levandowski’s employment contract with Google.

It turns out that Waymo did bring legal action against Levandowski back in October, according to a document filed by Uber’s attorneys today. In the arbitration demands, Waymo focused on Levandowski’s efforts to poach employees from Google, saying that he “improperly used Waymo’s confidential information to induce Waymo employees to join a competing driverless-car enterprise” and used confidential salary information learned at Waymo to make targeted salary offers. (In its lawsuit against Uber, Waymo claims that two other employees stole confidential documents in their final days at the company before joining Uber’s team.)

However, Waymo’s allegations of trade-secret theft weren’t included in the arbitration actions — and Uber is arguing that they should be. Of course, this would get Uber out of most of the claims in what’s shaping up to be a costly and reputation-damaging legal battle. The patent infringement claims would continue.

“Waymo asserts no claims for trade secret misappropriation in those arbitrations. Waymo’s purpose for proceeding in this curious manner seems clear: through artful pleading, it hopes to avoid arbitrating the misappropriation and UCL claims at all costs,” Uber’s attorney argues.

The two self-driving titans are due in court in early May.