The heal granted by Into the Fray is in no way dependent upon your Reactive Shield. Into the Fray increases the duration of Reactive Shield by 3 seconds. Entirely separate from that effect, Into the Fray also makes you regenerate 2 energy cells and heal for 2.5% of your total health when suffering direct damage from area effects.
Mr. Peckenpaugh, you might be right, but I can't seem to recall the powertech version of the skill ever healing me on the pts when my energy shield was not up. Granted I only played like 10 warzones. When 2.0 hits, I'll be sure to get back to you on the change.