This part is when you first witness Takuma on the roof of the tower on the first mission.
Defeat the three enemies that ambushed you, then use the stairs.
The yellow loop on the tower to climb is located by the two gunmen already opening fire (You may eliminate them if you wish using Shadow Mode with Hayato/Mugen, but in my case it wasn't necessary).
Because of that, this shouldn't cause an issue so climb up and then walk and meet with Takuma and you'll earn the trophy automatically.