I expect that behaviour (organising a fight in the kitchen) from teenagers, but not from grown men (Rooney is a father).
If they wanted to practise their boxing skills, then they could've gone to a boxing gym, where they'd be taught properly to box and could've had a nice, long sparring session.
In the right environment, boxing is relatively safe.
And judging by Rooney going down to easily, he isn't cut out to fight, so should stay well away. I didnt think that a professional elite level athlete can go down so easily.
Can you imagine the furore which would've resulted if he hit his head and ended up in hospital.