Scholarly citations to Plato’s Socratic dialogs typically use a system of marginal page numbers that appear in most printed editions, and which I believe come from an original Oxford edition of the text. This quotation, which I found in “Plato: The Collected Dialogs”, Edith Hamilton and Huntington Cairns editors, Princeton University Press 1961, is at 28b. The Huntington and Cairns volume includes the Hugh Trendennick translation, which I’ll copy here:
“You are mistaken, my friend, if you think that a man who is worth anything ought to spend his time weighing up the prospects of life and death. He has only one thing to consider in performing any action — that is, whether is is acting rightly or wrongly, like a good man or a bad one.”