Re: GM advice
All three games are combat-centric. Ignore what the blurb says about the settings, look at the amount of space in the rulebooks devoted to combat as opposed to other forms of challenge or obstacle. In DH you are supposed to root out and eliminate threats to society in the form of heretics, xenos or demons. The climax of the adventure will inevitably be the 'eliminating' bit. RT has the potential to create narratives with different sorts of climax, but in practice the rules militate against other forms of climax. Let me elaborate.
The rules make combat the only sort of conflict that can easily act as a climax. You set up a combat scene, and you're creating a 10-20 minute sequence (maybe longer) with the game mechanics ensuring that there is suspense, potential for phenomenal success, sudden reversal, catastrophic failure, and the ability for everyone to get involved (because like it or not, in a firefight the rules ensure that the only real difference between a combat and non-combat character is probably that the combat character hits around 20% more frequently - anyone can fire a gun that does a decent amount of damage). If, say, you have the climax as the PCs needing to defuse a bomb before it blows up, then you've got at maximum a five minute sequence (and that's assuming you add in some running around trying to find it, maybe some climbing somewhere inaccessible to get to it and a complex mechanism requiring several rolls to disarm) that only a few specialists can play a key role in whilst everyone else stands around watching. And the combat sequence essentially writes itself, with the rules creating interesting variety naturally (right, there's a psyker, so that changes the dynamics of combat like *this*) whereas in the alternative every obstacle requiring rolls and involving different skillsets has to be actively designed by the GM ahead of time. Combat is easier to set up and run and allows the whole party to affect the outcome. That's just the way the rules work.
Now, unless you're going to massively rewrite the rules, allowing other sorts of conflict to run on a combat-round type sequence with all players getting a chance to affect the outcome, combat becomes the lowest common denominator - the way to avoid having half the party standing around at the end with nothing to do. You can do this in a film or story - one character gets the chance to save the day by making a speech, flying the starship, defusing a bomb etc because it's fine to allow the other characters to drop out of sight for a little bit - but in an rpg you can't do it and have it last very long without most of the party getting bored. And most people being bored is not what you want at the climax of your adventure.
I tend to have combat as the climax to an adventure for all the reasions above, though I try to make sure that the party is actively trying to *do* something that the other side are trying to stop them doing rather than just throwing both sides into a room to kill each other, ideally giving a non-combat character a chance to shine in the middle of it. So, the scum must convince a diplomat to change sides whilst the rest of the party hold off the guards in the next room, the party must fight their way through the bad guys so that the adept and tech priest can attempt to decypher the archeotech device and deactivate it etc. This may give the feeling that the climax to the adventure is something other than combat.