It's one thing to physically impose yourself in a tackle, another entirely to deliberately knee someone. Did Mummy line up Murphy? I'd say definitely. Was his intent to hurt him? I'd say definitely. Did he deliberately raise his knee into Murphy? I'd say no. Did he intend to break ribs by sticking his knee/thigh into the side of Murphy? I'd say not.
Really, I'm seeing it he threw a deliberate knee into his guts. He went in there with intent and followed through to my eyes.