Modifying a WIM without mounting with Imagex

ImageX is all cool and everything but I don't have a second HDD partition to mount it and I read on a website you can't mount it to the C Drive with the Vista OS because when you mount a image it supposedly creates a MBR for some god awful reason. But I really need to open install.wim so I can pluck a file out, actually I want the whole i386 folder, I made a copy of install.wim so cutting and pasting rather then copying is not an issue. But I would really like to find a way that avoids me using Disk Management to shrink the volume because last night I tried to shrink the volume and it got stuck. I bravely backed out of mmc and restarted Vista and successfully kept my HDD intact along with my OS..... I'll never do that again. But I really need the I386 folder from that image and I think it's there I would hate to think ImageX is the only thing out there.