This is easiest to get when you first have to save the bot (Bot R103-A). On floor 85, use the bots abilities to swap the letters around to spell a word which contains 4 or more of the same letter. A few words which you can use are:
diddled
giggling
hillbilly
indivisible
sasses
voodoo
Personally, I aimed to get the word "sasses" as the letters are common.