During Truss's answer to the question about the confrontation between Russia and Ukraine, there was an unexpected rumble, which interrupted the broadcast. Talk TV later apologized for the incident.
"For viewers of tonight's The Sun Showdown, there has been a medical issue. It's not a security issue and the candidates are okay," the broadcaster wrote on Twitter, adding that the host fainted on air of the program. The host was fine, but could not continue the debate, it added.
Last week, the UK saw the fifth round of the voting in the Tories' leader race, with Sunak coming first with 137 votes, and Truss overtaking the third candidate, junior trade minister Penny Mordaunt, with 113 votes to Mordaunt's 105.
A total of 11 candidates initially announced their nomination for the prime minister's seat after outgoing Prime Minister Boris Johnson announced his resignation on July 7.