Q; Why didn't Troi use her telepathic gifts to communicate with the Away Team, specifically Riker, when normal communications were cut off by Armus?
A; My theory is that Armus, who I must remind you is quite unlike anything encountered before and thus likely to have hitherto inexperienced properties, denied her that privilege.
Q: Is it likely that Starfleet would send out officers equipped with such shoddy gear that phasers are prone to pop out of their holster just as Geordi's does here?
A; No. it isn't, and I surmise that that is not the case here. The scenario is that just as Riker is pulled into the gloop, the camera angle is at virtually ground level, and we see a phaser plop into said gloop just as if it had fallen from Geordi's holster. We don't actually see it leave the holster, mind, because the camera angle is so low we can only see his legs and them only from the knees down. One might surmise that Geordi, who remember was not with the first Away Team and didn't therefore see how Armus seemed to feed off phaser fire, instinctively drew his phaser and was going to shoot. Data, who was aware of the futility of such an attack, knocked the phaser from his hand, from whence it fell into shot again. And there you have it, dear reader, a perfect explanation.
Ha! What I think really happened was that the damn thing fell out unexpectedly, but being professionals the actors carried on filming. Strictly speaking, in my opinion, the scene should have been shot again, but if I were Jonathan Frakes I would have objected strongly at being forced to dunk myself in the gloop again. Wouldn't you? (Not that I'm suggesting that he did, mind). Then again, when the actor actually went into the gloop, he had his back to us, so perhaps it was a stunt guy. Who knows?
Picard leaves Worf in charge of the ship with the words, "You have the Conn." Doesn't he know that this is TNG and that one is supposed to say "You have the Bridge?"