I stand corrected sir.Boiling water does not need to be a likely cause of death; however, it indeed can cause significant & serious bodily injury. Thus it would be a justifiable defense if the defendant can articulate to a jury's or judges satisfaction why he thought it was such a threat in the given situation. Note, I am not making a judgement on the officer's actions nor on those of the deceased; I am only saying, without a doubt, that boiling water, in a substantial amount (such as a potful) hitting you anywhere, especially on exposed skin, can cause serious bodily injury.
source: https://statutes.capitol.texas.gov/Docs/PE/pdf/PE.9.pdf