AIs with grenades...interesting topic..always is with every modern military shooter. The prior posts adressed much of what to do (either be faster and kill them or learn to strafe and run like hell)
Of course...there is the less mentioned sadistic tactic...
1. make sure said bullet-eater is near some other bullet-sponge.
2. Flip the selector switch from "Safe" to "Rock & Roll" (ie whichever RoF you normally prefere)
3. As bullet-eater pulls the pin...kill him
4. Former Tango drops a LIVE grenade among his buddies.
5. Rack 2+ kills with one shot.
6. Wash, rinse, repeat.