Those interrupting the proceedings included Republican lawmakers who are allowed into the secure hearing room - because they are on one of the three committees involved in these closed door depositions - Intelligence, Oversight, and Foreign Affairs.
Democrats labeled the sit-in a political stunt that smacked of desperation.
"Trump wanted a foreign government to investigate his political opponent," said Rep. Tim Ryan (D-OH). "That is a crime."
“Today's circus-like stunt will delay but it will not prevent our search for the truth about the president’s stunning misconduct,” said Rep. Val Demings (D-FL).
"GOP "storming" a classified deposition was a ridiculous stunt," said Rep. Carolyn Maloney (D-NY).
Democrats also criticized the GOP effort for violating rules on security, as a number of Republican lawmakers brought cell phones into the secure facility, which is prohibited.
It resulted in officials having to conduct a sweep of the rooms, to make sure no electronic devices had been left behind.
"You may wonder why is it happening now?” asked Rep. Ted Lieu (D-CA). “Because Bill Taylor gave a devastating opening statement yesterday. They're freaked out. They're trying to stop this investigation.”
Taylor is the top U.S. diplomat in Ukraine - he testified Tuesday before investigators, making the case that President Trump was withholding military aid for Ukraine in a bid to get the Ukraine government to publicly announce investigations which might help Mr. Trump's re-election bid.
In a tweet on Wednesday afternoon, the President took direct aim at Taylor.
Reports indicated the President may have been told by allies in the U.S. House of their Wednesday plans.
“This looks awfully like obstruction,” said Rep. Don Beyer (D-VA).
After ordering some pizza and refusing to leave the room known as a SCIF - Sensitive Compartmented Information Facility - GOP lawmakers moved on after about five hours, as Laura Cooper, a deputy assistant Secretary of Defense began her testimony around 3:15 pm.