Elon Musk arrived in Beijing on Wednesday, as his $150 billion civil lawsuit against OpenAI CEO Sam Altman played out in a California courtroom. 

Whether Musk, the world's richest man, should have traveled abroad during the trial is a question that could come up in court.

At the conclusion of Musk's testimony in late April, U.S. District Judge Yvonne Gonzalez Rogers of San Francisco told Musk he was subject to recall, meaning he could be brought back to the stand for further testimony, at the request of attorneys for OpenAI.

"Mr. Musk, you are not excused, but you can leave for the day. Okay?" Rogers said to the Tesla and SpaceX CEO and X owner, according to a transcript of his testimony. 

Because the trial is in civil court, Musk, despite being a party in the case as well as a witness, was not required to attend in-person for the entirety of the trial. The judge did not explicitly direct Musk to remain in the proximity of the courthouse or not to travel.

Musk boarded Air Force One Tuesday and flew overnight to China. He and several other business leaders were invited to travel to Beijing with President Trump, who is meeting this week with Chinese President Xi Jinping.

The last day of testimony in the OpenAI trial was Wednesday and closing arguments are scheduled for Thursday, meaning Musk will almost certainly be absent for both. 

Musk didn't immediately answer a request for comment from CBS News.

Musk and OpenAI CEO Sam Altman co-founded the company as a nonprofit in 2015. Musk has since left OpenAI and is now suing Altman, alleging he flouted the nonprofit's original mission and is prioritizing profits. Musk is seeking to have Altman removed from the company's board, the company reverted back to a nonprofit, and have millions to be transferred to the charity arm at OpenAI.

OpenAI counters that Musk is looking to boost his own firm, xAI.