Init:
Elite 1
un-named cadet
Drackalicious
Derek
Will
Grunt 3
Rouge
Grunt 2
Mik
................
Jackson
Grunt 1
Nina
Grunt 4
As the two grunts come down the stairs, the party reacts quickly, Drackalicious moves back behind his partial cover as he takes aim at one of the grunts and releases his charged plasma bolt. It flies out, but at the last second it ducks out of the way and the bolt doesn't seem to curve at it like it did with the elite. The plasma pistol then springs open with its cooling vents pumping out air as hot as steam, Drackalicious, caught by surprise manages to dodge getting badly burnt but drops the pistol at his own feet.
Derek acts the same way but on the other side of the stairs, he moves behind cover and opens up with a torrent of fire (Taking this to mean a full auto) at the grunts on the stairs. A stream of blue plasma blasts out of the gun but Derek has not mastered how to use this particular weapon yet and the bolts miss both grunts by inches, one falls to the ground after dodging while the other keeps it's feet, still ready to fire.
Seeing the predicament they are in now, Will decides that despite being a tech, he has to step-up and take out some aliens. He spends a luck to ensure success and opens fire with his pistol, nailing the little alien clean in the... sort of ... vaguely chest type of area... he thinks. Blue blood comes out though so he knows he scored a clean hit. He then tries to make himself as small as possible behind cover.
Grunt three then takes his cue, but is currently lying on the floor so quickly gets to his feet and opens fire with his plasma pistol. the one who stole his commanders gun is clearly the best target so that is who he shoots at. he opens fire at Derek who is trying to hide behind a small crate that isn't big enough to cover his body, the plasma flies right at him and hits the box right in front of his face, just giving him time to duck, Derek knows that if he hadn't been in cover, that was going to get him in the head.
Rouge then opens fire with the AR he had taken after Jackson dropped it, firing twice, once at each grunt. He misses the first but hits a burst of fire clean into the un-injured grunt and watches it stagger back, clearly wounded.
The second grunt then finally gets to act, firing at the weird thing that just injured it, he fires at Will, barely missing the cadet. Will feels the heat of the bolt passing a few inches away from him. Mik then opens fire with the plasma pistol he had picked up. He is unsure if he would have hit the wounded grunt or not but the grunt panics, slips on its own blood and falls head first into the bolt. It doesn't move again.
Jackson runs behind cover as he does not currently have a weapon and uses his threat assessment abilities on the grunts, calling out his finding. "The grunts are clearly weaker than us individually, low accuracy and easily startled and scared. They should only be a big threat in larger groups or when lead by an Elite. The Covenant should know this, expect more of them!"
As if reacting to his pronouncement the team sees another grunt rounding the corner of the stairs and firing at Drackalicious, luckily the mention of their bad accuracy was also true and the bolt hits the floor over a foot from the Cadet.
Nina then shouts "Fire like Russian!" and opens up full auto on the two remaining grunts on the stairwell. She holds the trigger down until the clip is empty then ducks back into cover to swap clips out. One grunt is doing a great impression of Swiss Cheese while the new arrival is clearly gravely injured but still standing.