After some consultation, a revised IPS logo:
IPS logo draft 2.
The slogan was a revision based on a friend's suggestion: "Amidst Them All" implies they are more part of the situation they're patrolling, rather than merely standing "between" others. I also thickened up the stroke width on the logo itself.
I also have a rough draft of the insignia for the Old Way, the belief system that plays a prominent role in the story:
Old Way logo draft 1.
New York City
Other Lives Of The Mind