There are accounts by Thayer, Woolner, Daly and Rheims of shots around the launching (using the term loosely) of the last two collapsibles (C and A) on the sarboard side--this is where the celebrated suicide/murder claim comes from. Others, notably Rowe, Pearcey and Ismay himself denied that any disturbances occurred in the launching of collapsible C. By contrast, as Lord writes, there is only one thoroughly documented shooting on the Titanic--that was by Lowe during the loading of lifeboat 14.
In any case, a careful reading of Buckley's testimony, it seems to me, makes it unlikely that collapsible C was the lifeboat Buckley entered. Buckley testified that he helped in the preparing and launching of five lifeboats and to have jumped into the sixth. One can infer these were lifeboats at the rear of the ship, which were launched within minutes of each other. In what sense collapsible C would have been the 'sixth boat' is unclear.
Moreover, Buckley does not refer at all to heading to the front of the ship to get to the sixth lifeboat. And if we are to believe, as Quinn contends, that collapsible C was launched at 2AM or so, would Buckley have completely left out the fact that he entered one of the last boats on the ship, the one which the famous Ismay had also gotten into? Seems unlikely, doesn't it?
DG