LYNN – A 20-minute drama teetering on the brink of tragedy ended Wednesday afternoon when Lynn and Massachusetts Bay Transportation Authority police officers convinced a man to not jump off the commuter garage.More than 50 onlookers stood on Market Street watching the drama as the man, who appeared to be in his 20s, stood on an outer ledge of the structure’s fifth level, drinking from a glass bottle and, at various times in the standoff, thrusting himself out from the ledge or holding on with one hand.At one point the man shouted to the crowd, “Somebody yell ‘jump,’ somebody yell ‘jump’ and I swear to God I’ll do it.” A police officer stationed on Market Street threatened to arrest any one who shouted to the man.Several officers stood yards away from the man on the top level of the garage until one managed to approach the ledge railing and begin speaking with him. Shortly before 2:30 p.m., other officers converged on the railing and pulled the man to safety as the crowd below applauded.The man was taken to a waiting ambulance.