Rocco didn't like when he told get rid of the bodies wanted to know Where's Mike?
He wasn't happy taking orders from Tom
I think events happened so quickly that Michael didn't have time to tell anyone other than Tom of the new arrangement. Hence the "where's Michael?" Well, maybe Neri. Remember that during the Johnny Ola meeting, Rocco was given the (highly important) task of feeding Ola's men. That's a pretty clear pecking order
All good points.
And, as Luca pointed out, everything after the shooting happened so quickly that Rocco didn't even know where Michael was
So, we have to wonder: how if at all did Michael communicate that Tom would be in complete charge while he was away--and that they were to obey his orders as if Tom were Michael? It must have been especially tricky for Tom because, as Michael told him before leaving, he couldn't completely dismiss the possibility that Rocco and/or Neri were in on the shooting
Rocco obeyed his orders after Tom's stern Rocco
I believe Neri and Rocco would know if Tom was issuing orders that is because this authority had been vested on Tom by Michael himself
Also Rocco would have been very, very scared how Rocco as the Security Chief had botched the security of the Tahoe compound fortress with sentry, armed guards, dogs etc. and how this security breach / lapse had allowed Rocco's boss, the Top Mafia Don's bedroom to be machine gun sprayed
