Gary Wiegert was listening with anticipation as Texas Sen. Ted Cruz implored delegates at the Republican National Convention to vote in the November presidential election.
"It sounded like he was building up to the endorsement" of Republican presidential nominee Donald Trump, said Wiegert, a Trump delegate from St. Louis. "And then at the last minute, once he said, 'vote your conscience,' I blew a gasket."
Wiegert rushed forward from the Missouri seating area at the rear of the convention floor.
"I ran as close as I could get, and I was yelling, 'Endorse Trump,'" Wiegert said Thursday.
Cruz refused to endorse his former presidential rival, leaving Wiegert and numerous other Republican delegates angry, frustrated and disappointed. Wiegert joined others in booing Cruz off the stage.
"I don't respect that man anymore. I would never support him on anything," Wiegert said. "To me, it was very classless. It was like playing a sport where you won't go shake your opponents' hand when they beat you."
Some other Missouri delegates also were displeased.
Cruz delegate Eric Burlison, a Missouri House member from Springfield, said Cruz may have done more harm than good for his own political career. He said Cruz would have been better off staying away and sending a video message like the one from Florida Sen. Marco Rubio, another of Trump's former presidential rivals.
Cruz "gave the most captivating speech of the entire week, and then it just turned (with) his phrase at the very end" about voting your conscience, Burlison said. "Either he knew what he was doing and he has a bigger plan or he may have miscalculated how many people in that room supported Trump."
Cruz had been greeted earlier in the day by supporters chanting "2020" - an encouragement for Cruz to run again in the next presidential election.
Burlison said he had talked with many Trump supporters whose second choice would have been Cruz.
But "I think (Cruz) lost all of those people" by failing to endorse Trump, Burlison said. "People that probably four years from now or eight years from now would have looked at him as being the next guy, he lost them. They will never forget that, and they will never forgive him for that."
Missouri Republican Party Chairman John Hancock said he believes that by not endorsing Trump, Cruz may nonetheless have helped rally Republicans behind Trump.
"I sensed a great deal more unity coming out of that building last night, though maybe he didn't intend it that way," Hancock said.
Burlison said Trump seemed to successfully upstage Cruz when he walked into the convention arena near the end of the speech, drawing the attention of many delegates.
"It was almost WWE fashion - it was almost like a wrestling event," Burlison said, and "Donald Trump clearly came out on top."