Only the speedy intervention of uniformed gardaí averted a much more serious situation while a prominent former referee who ran to the assistance of the official was struck by a hurley on the head.
Lismore will long bemoan this defeat. For most of the game they were the better side and looked probable winners but three second-half dismissals proved their undoing as the Gunners scored a brace of points that decided the issue deep into added time.
A draw wouldn't have flattered Lismore, and both sides would have settled for a replay when Andy Moloney landed Ballygunner's equaliser in the 63rd minute. However, the referee played almost two further minutes and in that spell Paul Foley and Tommy Power hit the match winners.
The opening half saw Lismore on top, with the majestic Dave Bennett at centre-forward unerring from both play and frees. The Gunners attack was often floundering and as so often in the past, relied on Paul Flynn for scores.
Lismore were five points to the good by the 28th minute, but most of the drama was to follow in a half which lasted all of 38 minutes.
First Bennett crashed a ground ball to the net from 15 metres but Lismore's defensive wall scarcely saw the ball when Flynn goaled from a 20 metre free on 35 minutes.
However, as tempers became increasingly frayed, speedy John Heneghan flicked the ball to the net two minutes later to give Lismore a deserved 2-9 to 1-5 lead at the break.
The Gunners came out on the restart with all guns blazing but Lismore had the first real goal chance, with David Howard blazing wide.
Then Paul Flynn took over, reeling off three points from long range frees in as many minutes, and 10 minutes into the half the deficit was down to two points.
Bennett, now at full forward, and Dan Shanahan lifted the siege with superb scores, and Lismore were stoutly defending a four point lead when corner back Michael O'Sullivan was the first to be sent off, for a second yellow card offence, in the 47th minute.
Three minutes later pure mayhem erupted in the Lismore goalmouth and the referee brandished red cards to Lismore netminder Brendan Landers and midfielder Michael Walsh, along with Paul Flynn, who is now ruled out of Sunday week's county final as a result of his dismissal.
Lismore brought on substitute goalkeeper John McGrath and took James Shanahan off, but with only 11 outfield players they were soon under the cosh. Tommy Power's pointed free and Gearoid O'Connor's 58th minute goal brought the sides level before Bennett nudged Lismore in front once more from a free.
Eventually the Gunners' numbers told and after Moloney's equaliser Foley and Power (from a free) landed the points that decided the game.
: Ballygunner: P. Flynn (1-8, 1-6 frees, 0-1 "65'); G. O'Connor (1-1); A. Moloney (0-2, 0-1 free); T. Power (0-2, frees); S. O'Sullivan, P. Foley (0-1) each. Lismore: D. Bennett (1-10, 0-7 frees); J. Heneghan (1-1); D. Shanahan (0-2).
: R. Whitty; N. O'Donnell. A. Kirwan. R. O'Sullivan; S. Frampton. F. Hartley. W. Hutchinson; S. O'Sulloivan. T. Fives; G. O'Connor. A. Moloney. P. Flynn; B. O'Sullivan. P. Foley. T. Power.
: B. Landers; Michael O'Sullivan. S. Kearney. Mark O'Sullivan; P. Howard. J. O'Connor. W. Cunningham; M. Walsh. D. O'Gorman; P. Prendergast. D. Bennett. D. Howard; J. Shanahan. D. Shanahan. J. Heneghan. Sub: J. McGrath for J. Shanahan.
: Michael Wadding.