Blake is still hit hard by the death of Gan and opts to go into brief exile on an apparently uninhabited planet for a short period while he gathers his thoughts and the rest of the crew gather theirs. It's all very nicely pitched and you can make your own mind up about how much of a grand dramatic gesture to play his allies Blake is actually making; for my money he's too dumb and straightforward for that and is just playing to Avon's cynicism at the end to try and maintain some sort of psychological advantage over his erstwhile ally. Avon himself is openly scornful of Blake in front of the others (who in this episode effectively form a three-person unit batted around between Avon and Blake, though there's time to suggest Vila is somewhat saddened by Gan's death, the pair having probably the least complicated and least qualified friendship between two regulars through the whole series) but there's no real sign of him making an actual pitch to follow him and leave Blake behind. You get the impression (perhaps minding the events of "Horizon") that he's aware he's not quite ready for either leadership or genuine independence at this stage but keeps stirring the pot anyway.
The plot of Blake on a living planet being 'adopted' by a parasite being named Zil is the episode's weakest area. It's a bit silly and a bit Space: 1999, despite some decent attempts at giving Zil alien speech patterns and mannerisms rather than just being some poor girl in a crap rubber suit. I mean, it is some poor girl in a crap rubber suit but at least some thought's gone in. It doesn't even really give Blake any chance to think things over despite a broad attempt to tie Zil's survivalist instincts into the need to keep fighting the Federation even after the Control/Gan setbacks. Really it's blatantly there to inject a little jeopardy for the good guys and to give Blake something to do and how half-baked and second-hand it is could well be a sign of David Maloney insisting Boucher actually put the crew in the episode. Because Boucher is absolutely fucking itching to write an all-Federation episode here.
While Blake is undergoing a metaphorical trial Travis is going through a literal one - having finally grown tired of his failures (and perhaps aggravated by his hesitation in choosing preserving her life over killing Blake in "Pressure Point") Servalan throws him to the dogs. The charges are the same massacre she was protecting him from in "Seek-Locate-Destroy" back in Season 1 and it's some much overdue movement in his personal arc, and in that of Servalan's who suffered from keeping him as her right hand after so many failures. Now with her influence any doubt of his receiving the death penalty is also being dealt with when she arranged for his defence attorney Thania to stymie his case.
The whole plotline sees Boucher push the Federation beyond the faceless Big Brother business of the first season, and making Federation troopers and officials more rounded and human (but still not necessarily nice people) will be one of Boucher's tropes going forward. The arbiter of the trial, Samor, is painted as a grand old admiral who still thinks the Federation has some military honour; Rontane and Bercol, the scheming pair also first seen in "Seek-Locate-Destroy", make a reappearance while even two guards are fleshed out. Trooper Par especially is an excellent character, a plausible front-line soldier who is totally pragmatic and utterly without remorse for his part in atrocities yet still possessing some sort of internal value system, professing to thinking Travis wasn't a particularly fair commander but one that didn't get his men killed needlessly - something which, as a man who hasn't been killed needlessly, he has some gratitude towards. Travis repays this some small way but knocking him unconscious rather than killing him as Par refuses to shoot him, a strange little relationship but one that's all the more powerful for showing some tiny spark of humanity remains in both.
Brian Croucher is really growing into the role by this point. He looks like enough of a squaddie to pull off the military dressing while his surliness and simmering anger fit wonderfully with Travis' key outbursts to Thania, Par and Samor. Stephen Greif probably would have played it bigger and broader to detrimental effect; Croucher is certainly better suited to the character from this point on, hovering on the brink of sanity. Jacqueline Pearce is good again here, out-thinking basically everyone and keeping her hands clean of the whole business. The elimination of Rontane and Bercol is probably an obstacle out of the way as she eyes the big job and I love how utterly unflustered she is when a gun-toting Travis barges into her office. Once again she dominates him totally, and while it seems she's capitulating to his demands she's actually just using him once again, instantly having a plan on the table that suits her. She's even got a Mutoid crew on standby near the ship, and even after Servalan commands everything into place Travis still can't just shoot her in the face.
Travis is of course freed when the Liberator crew make a cathartic hit-and-run on Space Command, scoring a direct hit on the trial room and killing all in attendance bar Travis when the doors seal to prevent decompression. It's a heck of a contrivance but the irony is so fabulous it's justified - in trying to make some gesture in remembrance of Gan, Blake and the crew not only spare Travis death but deliver him into Servalan's lap as an unregulated weapon while removing some key obstacles for her. It's possibly the most B7 moment ever - had they not made that attack Travis would have been sentenced to death, possibly spilled the beans about Servalan's various misdemeanors and led to an overhaul of Space Command. Sure, the Federation would still have been a military dictatorship but one unlikely to give the Liberator crew a huge amount of bother. On top of that they're oblivious and even end the episode with a silly little joke.
While "Pressure Point" upped the ante "Trial" takes it even further, effectively mapping out the second half of the season, breathing new life into Travis and Servalan while making a fair job of realigning the status quo on the Liberator following the loss of Gan. And it does all this while being smart, entertaining and imaginative. Super episode.