The hieroglyphs given in your sample do not mention "vengeance"; they literally say "wash heart". Taking vengeance is mentioned by the author as an example of how an ancient Egyptian might have tried to cleanse his heart, but the words taken by themselves (without considering what the expression might have meant idiomatically) don't say anything about vengeance.
Edit: the writing of "wash" in that example - feather, arm, water - looks correct to me for the imperative form of the verb. If you want to add the word "your", tack on one of the following after the heart and the short stroke under it:
- for masculine singular "you": basket with handle, Gardiner code V31
- for feminine singular "you": tether rope, Gardiner code V13
- for plural "you", either gender: tether rope V13, with single ripple of water N35 under it, and 3 short vertical strokes Z2 under that.
It's very difficult to give pronunciations for ancient Egyptian words because the vowels were not written, and in some cases the symbols used to transliterate the consonants don't correspond to how scholars think they were actually pronounced (on top of which, pronunciation changed over time). Take a look at the Wikipedia article on "Transliteration of Ancient Egyptian" to get some idea of the intricacies involved.
In
Manuel de Codage transliteration, "wash your heart" would be:
- iai ib.k (masculine singular)
- iai ib.T (feminine singular)
- iai ib.Tn (plural)
But remember that all the letters used here - even "i" and "a" - represent consonant sounds in the original language.