A top comment on the video you linked explains it. >FOR YOU GUYS WHO COULD NOT UNDERSTAND WHAT HAPPENED: CRAIG JONES HAD 1 TURN TO DEAL AT LEAST 7 DAMAGE TO OL

A top comment on the video you linked explains it. >FOR YOU GUYS WHO COULD NOT UNDERSTAND WHAT HAPPENED: CRAIG JONES HAD 1 TURN TO DEAL AT LEAST 7 DAMAGE TO OLIVIER, SO: AT THE END PHASE, CRAIG USED A CARD CALLED "CHAR", DEALING 4 DAMAGE TO OLIVER AND 2 TO HIMSELF, BRINGING HIM DOWN TO 1 LIFE POINT. AT THE DRAW PHASE, HE DRAWS LIGHTNING HELIX, DEALING 3 MORE DAMAGE, DEALING A TOTAL OF 7 DAMAGE TO OLIVER AND WINNING THE GAME WITH 1 LIFE POINT.