I would say that was the team that invaded the core, but Sub8 and Sub9 kinda make it a point that Murtaugh invaded by himself, I mean the dude has a karma arm afterall, I don't think he needs guns... but anyways, I get the picture that the guns were actually used by those who came after Murtaugh when he re-entered the core.3. What was the need for the limited appearance of firearms in Submachine?
I know the equipment cutting into the core wall was making it seem like that Murtaugh did it, but again, karma arm. I think the entire area in Sub7 was used as an encampment, or barricade. But Murtaugh was able to sneak in through the use of his portal ability, if he explored the subnet for 32 years, I'm sure he found plenty of clever tricks along the way.
I think the area with Liz's ship was not Murtaugh shooting at Liz, but the team shooting at Murtaugh and then he used the green portal to get to Layer 5. Is there any reason for Murtaugh to kill Liz? If anything, Liz was his sympathizer, that's why he couldn't see anyone else, he could only see Liz. Because she was the only one who understood what he was doing and why.
Sorry for off topic.