I believe that particular (mutilation) scene is based on an excerpt from Eugene Sledge's
With The Old Breed At Peleliu and Okinawa on which
The Pacific is partly based - although, I read that it is, rather than basing it on firsthand knowledge of the Sledge book. A related book which I doubt will have been referenced for this miniseries is William Manchester's
Goodbye Darkness which tracks his career as a Marine fighting from Tarawa through Peleliu to Okinawa. There's a particularly creepy part of the book set on Okinawa where as a dispatch runner, Manchester is pinned down, alone, by a Japanese sniper who keeps yelling "One Two Three! You can't catch me!!!" at him.
I am keeping an open mind watching this miniseries - I mean, I've pretty much given up on ever seeing a war movie that's accurate by any stretch of the imagination - I can already (without having read any of Leckie's writing, and therefore without the benefit of knowing what's to come) see that the Bob Leckie character is headed for PTSA, which is, from what I understand, partly the angle of
The Pacific as a cinematic undertaking. Unlike
Band of Brothers, this is not necessarily going to pay homage to the fighting men of WW2 via the exploits of E Coy., 506 PIR, but rather look at what almost unimaginable horrors fighting men have to endure, and then what happens when they're sent back home and expected to fit back into the lives they left behind when the war started.
That said, I'm always amazed when somebody who couldn't tell Akira Kurosawa from a dead crab all of sudden thinks they've got a Ph.D in film studies because they can tell a rebuilt OT-810 from an SdKfz 251.