How long until Prof X is gone?

So they added 6*s into the game? 😁

I haven't kept careful track of these things - maybe I will for the next PVE, it might be interesting - but I can add this - I entered the first SCL10 they implemented (Honor Among Thieves) one sub late. I was waiting for the bracket to flip -- it did about halfway through the second sub. I did semi optimal play - clearing the sub more or less when it opened (taking my time, but generally within 2-3 hours) and trying for a full clear on the close. Because it was the first SCL10, I mis-timed my final clear and definitely missed a few nodes past checks (sometimes the Bonus Node, it can be incredibly time consuming.)

I made progression very early on in my final clear. So it is still very possible to get full progression if you miss the first sub, even on a 3 sub PVE. I strongly suspect you can skip any particular node (for example, the 5* node if you don't have the 5*, which may be the case if they require Havok next week,) and fairly easily make progression if you try hard enough.