So, what's techni'kal in "Su'kal"?
Spoilery things first: we get a future holodeck... malfunction. Of a perfectly excusable sort, since the machinery is bombarded by what gets called "ionizing radiation" in refreshingly uncomplicated technodialogue (although there's also "subspace density interference"). There's visual glitching and looping, but the Vulcan in (Burn-era-appropriate?) Starfleet uniform hiccups in an informative manner, explicating the mechanics of skipping and accessing necessary to arrive at a desired subroutine.
We learn nothing specific about the functionings of the holodeck, as our heroes either lose their tricorders or are fooled into thinking they lost them. Is it forcefields and light shows, or replication, or programmable matter, or what? We don't see glimpses of a grid, or user interfaces, or anything of that sort yet.
Where is this holodeck? We see a split-obelisk shape on Bryce's display, probably the outline of the Khi'eth. Is the ship still that intact, or is that archived information on her and the reality is more gruesome?
Since everything down below on the ship/planet is make-believe, the tech meat is in the way Osyraa captures the hero ship. Physical tentacles plus penetrating transporters do the trick all right. I can see the defenses failing, but how come there is no intruder alert?
Key technologies involved in the capture: a mind control cap for Stamets, an alleged means of analyzing and tracking the "signature" of the spore jump (something the heroes themselves seem to believe in, even if Osyraa in fact is operating on data from sinister agents and infiltrators instead), and perhaps something in those tentacles to make them couple the Viridian to the Discovery so that both jump in unison (is that what automatically happens, or did Osyraa need to acquire special technology for it?). The Emerald folks exclusively sport the familiar folding guns also seen on Zareh's goons in "Far From Home". Why are only the two who grab Stamets wearing helmets? (And do those come with mind control caps built in, considering the detailing?)
The Discovery now has a cloak, and even the Emerald Chain can't penetrate that one. The interfering nebula might have something to say on that, too, although to helpful or hindering effect, we can't readily tell. Osyraa's camouflage may be cloak-based, too, or at least has telltale neutrino activity á la ST6:TUC. Her ship now has lots of extra texture compared with the previous appearance, and lots of portholes lit in the "darkness" of the nebula.
When there's a mini-Burn, and the warp core is in jeopardy, Stamets is the boss of the emergency response - the de facto Chief Engineer after all? If Reno had any sort of status, she wouldn't hold back there. Instead, she just acts. And Nilsson is... Somewhere. Probably donning a new alien head, while many of her colleagues appear without their usual ones.
The response involves locking down the magnetic constrictors and purging the dilithium chamber, both of which sound like sensible things to do, but also like things that wouldn't make a difference unless implemented in a picosecond...
The Viridian gets affected, too. Oddly, Osyraa positions her bow first to the heroes, even though she arrived edgewise and turned her turrets to execute a broadside. Perhaps she's drifting there and thus having to choose this less than optimal angle?
The McGuffin world is V-Class on the displays. A so far unused letter - appropriate for dilithium spheres like the one from "Pen Pals", or for planets that are no longer completely there / no longer quite spherical?
What did Detmer manage to punch in to her console before being stopped?
Timo Saloniemi