The grenades might have been mostly harmless to The Spoiler, he still didn't want explosions disrupting his position.  Waving a hand, he used his stolen telekinetic ability to fling the grenades aside, preferably in the direction of the ambushers but certainly not at Tatlelik's unit.  He made his way to the correct spot, keeping his facing toward the ambushers but his attention more on the Whitewater unit, and waited for the appointed time.