I generally hit halo at -2 seconds, then Pot then mindblast, The mind blast hit will land directly on the pull. Then SWP, VT, Flay till next MB, Normal rotation would continue from here.
In the case of protectors with multiple targets, when he would normally go to flay, he'll apply dots to the other targets instead, ideally starting with SWP on both then VT. Switching targets mid cast removes the delay.
If he starts with 3 orbs (probably isn't) use VT instead for the cast time spell then SWP, DP, MB and finish off the insanity.
Note the last four lines, He cast Flay, MB, SWP, DP then insanity. If he's properly planning ahead, He would have been able to refresh SWP early in the spot that he used the flay and gone straight into the devouring after mind blast, Allowing for 1 extra GCD of Insanity.