For those of you who read Narbonic...
I believe they've changed the future as of tuesday's strip.
Future-Dave's holographic message to Past-Dave had concluded with "don't forget to fill the swimming pool."
Helen just had a safe landing in a full pool.
My assertion: in the alternate history of these events, pool was empty, Dave rescued Helen's brain and put it in a jar, Mell takes over, future unfolds as we saw.
This time, Helen survives the fall, things have changed, future is uncertain now.
Brilliant.