Lapuaho recovered a fumble and it was clearly a dead-ball (clear possession and down on the ground) when the BSU speared an unsuspecting Lui. Could have seriously injured him. I'd have been pissed too and would have likely acted the exact same way. IIRC the official was standing right there and did nothing about the initial late hit on Lui. I don't remember if it was flagged or not but I don't think it was. Probably because the ref knew he should have thrown a flag on the initial hit.