Responses

I think he already gave up on trying to live, he simply got rid of the gangster in an efficient way to make sure his partner would not get hurt. If he was to slowly walk towards the gangster and buy time while saying things, there is no guarentee the gangster wouldn't shoot and therefore killing both him and partner. But, to be honest, he could have just ran up to the guy and slap the gun out of his hands/punch him as opposed to falling of the building as we already see how athletic his body is ┑( ̄Д  ̄)┍
I can't help but think that there had to be another way to stop the gangster, where he could live