Never seemed to me like the left that finished the job, should've finished the job. Didn't really seem to have that much leverage and power behind it, but I guess it could've been a temple shot that was worse that it seemed. If I was to choose a side, I'd say he simply had enough that night
To be honest it does not look like a quit job it looked like an old fighter got hurt and beat up somewhat he didn't look like he was riding the count out
Like people have said, the impression I've always had is that Ruben had had enough and maybe could've beaten the count. I don't consider that the same thing as quitting though.