@thewizardguythe sergals coming across the automated defenses just sort of blow it up as it begins warning them, their scans reading the remnants from the turret before marking their maps to be able to spot them within a radius before they came across them and move on, taking out the turrets when they get within firing range (which is actually remarkably far).
The second group took up a defensive position as they advanced, the tyranids popping up sporadically with either ripper swarms or hormogaunts, all the larger life-forms staying further in, the tyranid infection having been spreading rapidly since their arrival, leaving the ship's defenses being assaulted from inside, the rippers doing a number on the various wires and tubes while the hormogaunts destroyed the drones.
The swarm stirs at the smell of fresh bio mass, hormogaunts and termigaunts pouring out of the walls and under the grated floors to rush at nathan and the seragals with him, teeth nashing and blades flashing, the sergals doing their best to gun them down but there were only five of them against a horde of hungry tyranids. Matt, on the other hand, was not quite so luck as he was trapped in his safe room, the first four levels of defenses having already been breached by the tyranid spore clouds, eating away at the ship through the vents and slowly making their way to him as he's able to see the largest creatures to be right outside his position, leaving him nothing more to do than cower and pray for help to arrive quickly