I would like to be able to say that "Litmus" is a wonderfully written, tightly acted and directed script, about what happens when paranoia is unleashed. It is. I'd also like to say that the script is original and will you have you sit back in your seat and say "Wow, this is truly excellent."
The episode begins with an old friend walking down a Galactica corridor. Tigh and Adama see him at the same moment and recognize him - they stranded him on that isolated re-arming post quite a bit earlier. Then Doral blows himself up. Seems someone left a hatch open somewhere and he was able to access a weapon's locker and strap a bunch of explosives to him.
Luckily: he blew himself up when he was identified and wasn't able to reach a critical section of the ship.
Unluckily: several people are killed, and several more wounded.
Adama puts Master-At-Arms in charge of the investigation, but she requests permission to go wherever the evidence leads - regardless of rank. Probably the one scene that just screams "STAR TREK THE NEXT GENERATION!" is that where a Marine arrives at Adama's quarters with orders to bring him in front of the tribunal.
Master-at-Arms investigation focuses on who left that hatch open. Seems the hatch leads to an armory where, after the explosion, crewmembers find the Marine who was standing guard, dead (by Doral, duh). Of course, it just so happens y'know who and who were getting it on, so the deck crew tries to protect Tyrol -- all of them providing different alibis for the Chief, which of course only provokes suspicion in Master-at-Arms, who hauls both Tyrol and Sharon in front of the tribunal.
Master-at-Arms seems less concerned with finding out who was responsible for leaving the hatch open then with establishing her own innocence. "If you'd told us they looked like humans, we could have changed our security procedures. It's your fault, waaah."
There are things to like in this episode -- Chief Tyrol has two intense scenes, one with Sharon (where he ends their relationship); and another with Adama (where he admits his guilt in the hopes of freeing the kid who is in the brig for lying under oath - to protect Tyrol). I'd like to say the scene with Adama ending the tribunal was also good, but again, it was just in tone so close to TNG that I couldn't bear it.