Can we add tum to thut and then make it work? No, you have a twum. Adding something more making sense does not make sense. It will not give the meaning of inocida and the rue pashevoham. That ultimate result which we are looking for won't come this way. Then thereis one more option in sanscrit which is called jahd ajahat lakshana - allowing you to keep part of the original meaning and give up some incidental, accidental, superimposed, unimportant aspect. The example which they gave is so am devadate. This is that devadatis, just a guy. Imagine you met deved
Sage Uddalaka asks his son Svetaketu: What is that knowledge by which we hear the unhearable, perceive what cannot be perceived and know what cannot be known? Inspired from this story from the Chandogya Upanishad, Swami Sarvapriyananda teaches the great saying (mahavakya) - Tat Tvam Asi (That Thou Art).
This discourse is also inspired from a verse from the Brihadharanyaka Upanishad (Mantra 4.4.12) as taught in the book, Pancadasi by Vidyaranya: "If a man knows the Self as ‘I am this,’ then desiring what and for whose sake will he suffer in the wake of the body?"
Mantra 4.4.12:
आत्मानं चेद्विजानीयादयमस्मीति पूरुषः ।
किमिच्छन्कस्य कामाय शरीरमनुसंज्वरेत् ॥ १२