Take cover

Who: Cerebrum, Keto, Appendix, Cerebrum's unconscious men, the mad
computer
Where: If you don't know, then you haven't been reading the previous
posts
When: Now
Cerebrum walked in through the door, after his discussion with
security. He noted his unconscious men, and the odd burn on the floor
that looked like his Meson Cannon had fired a shot.
"Appendix, I thought you said Keto was here?" he asked.
There was something that sounded like, "Yes," which was cut off as
the meson cannon fired a blast at Keto.
[Keto is here, your weapon's been firing at him.]
"It's not a weapon," Cerebrum said indignantly, "it's a device that
on lower settings fires a narrow beam capable of affecting various
parts of the brain in a beneficial way, and on the higher settings
fires a beam that can punch through the side of the ship. But it is
most certainly not a weapon. Anyway, it has no automated procedures,
unless an AI were to operate it through the computer that I hooked up
to it. And also, I can't see Keto."
[He's invisible.]
"Dr Keto's invisible? Lovely. Tell me, have you been affected by all
the diseased minds you read?"
[No, really. And your device is firing at him.]
Cerebrum walked over to his unconscious men and took a wrench out of
one of the toolkits. "Look, if Keto were invisible, then this wrench
would hit something if I swung it through the air right here."
[I wouldn't do that]
"Let me show you that he isn't here," Cerebrum said, then raised the
wrench to swing it through midair. In a normal universe, he would
have swung it and it would have gone through the air as dictated by
the laws of physics. In this universe, a blast from the meson cannon
vaporized it, then it started taking aim at Cerebrum. (OOC: Bet you
thought I was going to hit Dr Keto with it, eh?)
Cerebrum didn't spare a moment, but sprinted across the room and
dived behind his desk. Dr Keto, who had taken the opportunity to do
the same thing when the meson cannon aimed away from him, also dived
behind the desk, and the two Doctors' heads collided.
"What?" Cerebrum said, "Is that you Keto?"
"How many other invisible doctors are there on board this ship?" came
the reply.
"Don't know, I'll take a survey."
"Of course it's me!"
"So the Appendix was right, you are invisible. Fascinating."
"What gave you the hint?"
The bickering would have no doubt continued, but the meson cannon
fired a blast over the top of the desk, and refocused their attention
on important issues, such as survival.
"I don't get it?" Cerebrum said, "It shouldn't be firing at us. It
has no automated procedures, the controlling device is the computer
that I borrowed from the science lab. They only reason that could
possibly cause this would be if the AI was corrupted and had gone
mad."
"Muhahahahaha!!!!!" the computer suddenly announced.
"Ah, that explains it. Five exclamation points, sure sign of a
deranged mind."