Ohhh, ok, I got Explode and Inflate mixed up.
But otherwise, it sounds like I had the “Pop first, then Explode” part right.
But to clarify more:
Let’s say the Rogue is Level 4.
That means I’m now rolling a 2d8 (Level 3 grows my class dice to d6, and Level 4 grows them to d8).
So 2d8 with Vital Hits means I initially pop on values of 3 or more still (that is, as I level up, I am more likely to pop because more of the possible results are greater than 3), and if any popped, then those dice can keep exploding only on rolls with a value greater than or equal to 5 (more than half of 8).