Not only that, but seasoned good common linesman scense says ... if your putting wet stuff on red stuff ... and red stuff isn't going away .... not enough wet stuff!!
it looks like truss to me because i cant see a large beam with rafters attached to it. the "rafters" on truss roofs connect to each other without a beam running across the roof
I have faught two fires very similar to this. We addressed the issue differently each time. The first time we used hand lines from exterior openings and had great success. The ISO was concerned about floor integrity from drop down burning, turns out it was fine. The second time we saw this was on a two story and the IC elected to put up the aerial and let fly. This turned out to be a great call since we had significant burn through from drop down. As an ISO I think you need to rely on your best judgement, and colaberate with the IC. The only two things I can't see here are FF's pulling ceiling or sounding the floor. Both of these actions, in my mind, would contribute to the success of the tactic applied in this photo.