I can't seem to be able to get control of Tommy during the cutscene. What am I doing wrong here? Up until this point I have done everything correctly, excpet getting to the hotel early enough apparently :^) .

You need to reach the stairs in the hotel before 21:47 ingame time.

The walking during the cutscene happens because the old marker from the first mission is still there if you make it early enough. You have duped markers at the point and the old tutorial marker is shorter than the bab cutscene. So you regain control earlier.

Ah I didn't know that was that important :/ Thanks for the explanation, it all makes sense now.