Would the first sentence using a comma be acceptable? Can this sentence be broken into two sentences, as in 2., or would that leave a sentence fragment? Or is 3. proper in its use of the em dash? Would someone mind explaining why a comma or separate sentences would be improper? I'm having a hard time grasping it. Thank you.
I had to clean up the apartment, put the electricity service in my name, and find a new roommate, all without proper notice.
I had to clean up the apartment, put the electricity service in my name, and find a new roommate. All without proper notice.
I had to clean up the apartment, put the electricity service in my name, and find a new roommate―all without proper notice.