The incident happened during the opening session of the semi-final match between Judd Trump and Mark Williams. With Trump preparing to take a pot, a knocking sound could be heard off-camera.
As the Crucible crowd roared with laughter, Eurosport commentators informed viewers about the disturbance. "Just a bit of noise coming from the host broadcaster's studio," they said, presumably referring to the BBC. "Desislava banged on the window and told them to keep quiet. That's the way to do it."
The interruption didn't bother Trump, who continued his domination of the opening session to take the final frame and with it a 7-1 lead against three-time champion Williams.
It is now a long way back for the Welshman, who will need to get off to a fast start in Friday's morning session. The 47-year-old said later on social media that it could have been 17-1 had the match been allowed to continue.
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"Sorry about that performance, very hard conditions for me I'm afraid, if we carried on there it would be 17-1 easily," he tweeted. Six-time world champion Steve Davis offered hope for Williams in his analysis for the BBC, but admitted a turnaround is unlikely.
"If your opponent does not put up any resistance it makes the job lot easier," he said. "It is a shock that Mark Williams has gone off the boil. We expected him to continue his form.
"It just shows you what happens in snooker if one player gets away from another. The other guy is reeling and has to wait for the session to end to mentally regroup.
"There is the possibility that roles can be reversed but it is unlikely."