Q: Aura: Sonic and Shadow should be here by now, what's taking them so long?

A: Meanwhile:

Sonic's fighting a dragon that was trying to destroy ponyville.

Meanwhile again: Shadow was just trying to get out of bed. He could barely stand. Once he got out, Pinkie pie came in to help him.

Pinkie pie: Shadow, don't strain yourself. If you do you'll get weaker, and your cancer will be harder to beat.