The trajectory remained the same. When Zoro blocks it you can see a ring from the attack being launched and it already shows the same direction in which it later goes:
Just look at the 'ring' in the first image and you can see the attack was upwards since the beginning.
If the trajectory was being changed, there was no point in the sn escaping from it, and we can see that happening. Law just teleported everyone out of the attack, including Zoro, that's why all of them are on the same location on the next page, if they ran and Zoro remained there, he wouldn't be in the same place as them.
I think we are taking the angles of drawings a little too literal here lol....there's no indication he changed the trajectory, just slowed it down. If Oda wanted to communicate he did that, he would have made it far more obvious like he has other times with other characters