Britanny Man, no translation, here is the text from the book, page 123, Bantam Edition, the chapter on the The Mohan Man Eater:

"And now, for the first time in my life I regretted my habit of carrying an uncocked rifle. The safety catch of my 450/400 makes a very distinct click when thrown off, and to make that sound now would either bring the tiger right on top of me or send him down the steep hillside without any possibility of getting a shot"

"Aligning ths sights of the rifle on his forehead I pressed the trigger, and while maintaining a steady pressure on it, pushed up the safety catch. I had no idea how this reversal of the usual method of discharging a rifle would work, but it did work;"

The 450/400 used has been featured in a thread on this site. It is a boxlock Jeffery.

The inescapable conclusion is that Corbett assumed that putting the gun on safe uncocked it. The safety does no such thing.