I feel like they were being playful? I haven't seen the full thing though... He clearly isn't being serious when he said he's going to kill her, it was in jest.Well, there's this clip of him elbowing her:
Then there's one where he apparently says he's gonna kill her while she's trying to end the IG live but I couldn't find it.
Also the way he looks at her...no sign of love, just annoyance and anger.