Sure, in real life, if Omar had been a big-time operator, Tony would have been dead real quick. But it was Filmic License: That scene was used to establish Tony's reckless, risk-taking nature, and Omar's basic lack of cojones. It also set us up for the scene where Omar and Tony call on Sosa. Omar follows Frank's line and wusses out, but Tony, reckless and risk-taking as ever, shows his stuff. Result: Omar dangles from the copter and Tony's the big kahuna.