How did shining armor react to the invasion

Well, I know one reaction he might have, especially when he finds out that his wife was turned to stone:

"...MOTHERF-!" (cuts away before he finishes).

But seriously, he's pretty upset. As well as worried, due to the fact that one of the leaders of the Crystal Empire is out of commission. Further, he'd probably be worried that certain other powers in the world might be eyeing the semi-destabilized Equestria as ripe for conquering.

7259999 He retreated to the mountains to train Flurry Heart, so that one day she may save the ponies of Equestria.