mac: /usr/sbin/diskutil verifyPermissions / hangs in single-user mode

Question

I'm trying to repair my sister's iMac using single-user mode.

Since a recent power outage (no surge protector) it won't boot. I used verbose mode to see where it was hanging ("mDNSResponder: adding browse domain local") and found some advice online that said repairing the disk permissions might help.

So I booted into single user mode, ran fsck -fy a couple times until it stopped complaining, ran mount -uw / and autodiskmount -va fine, and got stuck at diskutil.

It just hangs (over an hour, no output).

Is there anything else I should try, or should I just revert to surgery and grab the hd?