24 across: Terror during lopsided tennis set has pulsating effect?
TC TH came up with the thrilling breakthrough: a lopsided tennis set is 6-0, or VIO. From that brilliant start, and with the help of a cross clue or two, it came to pass that terror = brat, lopsided tennis set = vio and terror during lopsided tennis set = vibrato = pulsating effect.
Update: There’s RC and EC, but there is definitely no TC. TH, please forgive me.