Soliola was on Tuesday night suspended for five games for the dangerous contact that knocked Slater out.
Evidence from Melbourne's head medical official, Dr Jason Chan, claimed the Maroons fullback was "unconscious before he hit the ground".
"Billy knew he was in Canberra, but not that he was at GIO Stadium or why he was there," the report said.
"He had no recollection of previous two weeks. Not aware he had played State of Origin, or that he had injured his ankle that week."