I think they had to get the center hung scoreboard in place up high to free up the floor space it occupied (or that it was hanging 1 inch or so from). All of most of the roof above it is still missing so it is still surely covered with protective plastic.
Like I said earlier today, a top priority is getting the floor of the dome resurfaced. Despite all the precautions they took with the wood, the floor got chewed up pretty badly and needs to be re-done. Once that has been done, they can put the field turf down. But before they can work getting the field in place, they need to get the cranes on the dome floor out. That means the new LED lighting, the new sound system, maybe some AC stuff, upgrades to WiFi...all that kind of stuff needs to get done. From the insider pictures, it looks like they are close to that point.
I assume the PTFE roof installation will be done completely from above. The tricky part, I think, will be when they finish installing a row of PTFE and need to move the safety nets from that row to the next row over. In theory, they can leave one side attached, detach the other and re-attach it to the next cable. They could do that using ropes, I think. Something to watch for as they get close to finishing the 4 rows they are working on now. Looks like it will be a few days before they need to think about this.
Regarding using the dome for classes...with the new social distancing rules in effect, all classrooms just shrunk by 75% or so. There is a need for larger rooms to hold classes. There is a need for spacious areas that are open and heated. The dome fits the bill perfectly. You could have a bunch of classes in there concurrently and not put anyone at risk. A bonus with using the dome for classes is that it will get cleaned more carefully and more often than ever due to the classroom hosting.