Continuity mistake: When Joe is walking in NY for the first time, his hat goes from being pushed on the back of his head to on top several times.
Continuity mistake: When Joe gets locked out of his room and loses all his possessions except for the clothes on his back and his radio, he's wearing his red western shirt. However, after Shirley, his only paying customer, gives him the $20 (cut to the next scene), and Joe returns to the X-flat with medicine for Ratso, he's wearing a purple western shirt and has this shirt on until he throws it away along with all his other clothes on the bus ride to Florida.
Continuity mistake: When Ratso finishes heating a meal he tells Joe on his bed reading a comic, to sit at the table and eat because it is hot. Joe gets up and puts his right hand on the chair - in his left hand is the comic he's reading. But in the next shot as he rests on the seat his left hand touches the table and his right hand now holds the comic.
Answer: Probably not. The man was a masochist who derived sexual pleasure from being physically abused. Joe apparently crammed the phone receiver into the man's mouth and left, unknown if he died from it or not.