Start the level on "Bad Blood" and proceed until you enter the base. Continue through the base until you reach a cut-scene where Turok mentions the planet being "Terra-formed". Continue to the right to a shelf containing some ammo and a grenade. Turn around and head left this time eventually spotting a helicopter dropping off troops. Continue until you reach a checkpoint. Three enemies will enter to the left. As soon as you see them, throw the grenade. If executed correctly you will kill all three with one grenade. If you miss, don't sweat it, reload the save point and you'll end up right before you threw the grenade.
I made this video a while back if you need more help.