I'd rather recommend booting a liveCD. grml, knoppix, whatever floats your boat. An init=/bin/bash shell needs quite a bit of knowledge to get working (mount rw, get rid of selinux, mount the real rootfs), is possibly just busybox and generally a pain. Even more so if you need the net to copy something over.

It isn't impossible, and OK in a pinch, but why make it hard on yourself?