The infiltration was a near disaster. Ain used too much stamina keeping them invisible and then didn't allow time to recover. This was mostly due to his own pride.
Fenn only seems a bit unsettled at having to kill, but only time will tell if it's a problem.
What's interesting is Ain being disturbed by his attraction to Fenn. His feelings are stronger than a casual fling would indicate.
It seems too soon to be sending Fenn out on a mission into enemy territory. The women who attacked Ain was able to detect him somehow. Have they forgotten this already?
Fenn is slowly gaining more self confidence under Ain's careful tutelage. The episode playing with the children helped him ease the deep seated shame he bears due to his powers.
From all we've seen Fenn is a good person at heart. Still being this way after years of mistreatment is a big positive. The power doesn't shape its user, its their heart and Fenn is good.
Ain is certainly smitten by Fenn, but his own virtue is loose. It might be for the best Fenn will not be an easy conquest. If love is hard won, it's worth keeping.
Fenn has found himself in the middle of an enigma. The Bulwark being hostile, the Herald supportive, and Ain being odd. I hope Fenn gets his footing soon.