Apologies for the bad recording, HULU doesnt let you record video.

It looked more egregious live than in replay.

I was worried he had a concussion because he couldnt stand up at first. I think he hit his head on turf.

Technically i think an illgal check because the Duke player looks like he goes out of his way to lean into the hit from the side/behind but on replay it doesnt really seem that forceful, just bad physics because Liam was in stride when hit which made him fall.

I'm not well-versed in LAX rules. In hockey at a minimum it is interference (forceful contact preventing free movement away from the main play), although I've seen cross-check or checking from behind called in this sort of situation as well. I've not watched nearly enough LAX to become familiar enough to know what (if any) sort of penalty can be called on this play.