Their microphones may be muted for anyone watching their debate live, but Vice President Kamala Harris and former President Donald Trump on Tuesday night are also sneaking in their own comebacks.

The Democratic and Republican presidential candidates had agreed to rules ahead of their showdown, including controlled mics and no audiences. Still, the reports from a couple of journalists inside the debate stuido in the National Constitution Center in Philadelphia reveal a glimpse into what viewers are missing on television.

Numerous times throughout the 90-minute debate both Trump and Harris audibly denied comments made by the other, accompanied by a variety of facial expressions.

More: Presidential debate fact check: Keeping an eye on claims from Trump, Harris

“That’s not true, that’s not true,” Harris said shaking her head in response to Trump claiming the U.S. does not make semiconductor chips.

The two joined in a heated exchange on reproductive rights where Trump claimed he was a leader on invitro-fertilization and that Harris supports abortion up until birth. “You have not,” she said. “Come on.”

“That’s just a soundbite, they gave her to say that,” Trump said in response to Harris saying “Trump doesn’t have a plan for you.”

This article originally appeared on USA TODAY: Muted microphones not stopping Harris and Trump from commenting