In Hall of Mirrors
Hit down x2, right x3
Pick up the glass shard next to the wombat, then click on the glass shard icon next to Rufus
Repeat 2 more times (3 hits total) – you need to pick up the glass shard each time
Wait for the wombat to kill the three Junk Knights
Pick up the glass shard and kill the wombat
This can be a pain as the wombat is random on who it attacks and you can die. If the wombat kills Rufus it will reload and you can try again.