[They take prisoners when they think they can be of use for experiments, or actively defect to their side. And by powerful psychics, it means "Unless they mentally whisper, normal people start bleeding from their face-holes and die and/or go screaming insane." You lot can withstand it, but a psychic yell is going to hurt. The psychic warrior backup can withstand it better than any of you. Incidentally, they'd most want to capture him.
A Vulcan is basically a high-caliber chaingun. They're similar to depleted-uranium shells.
High Caliber Carbine.
A Plasma Torch can be thin to cut, but in combat mode, imagine a hose spraying ultraheated plasma, or "Six foot long flamethrower/sword" that can run for about 2 minutes.
To explain the Blaster Rifle and Energy Pistol... well, file this under "Lies you can understand", but basically like ball lightning. They take a charge, and then accelerating that charge to the target. They're not the lightspeed shots of the Laser Rifle.
Toxin Rifle works exactly like you think it does. A dartgun that fires toxins.
Phased Pulser is a mid-range, high-power version of the Laser Rifle designed for bypassing armor.
Bloodcannon should read HP. You donate blood, it turns it into a bullet, and launches at extreme velocity. Not good against armor, damned good against flesh.
A monomolecular-edged sword. Very sharp, and with a liquid core that adds impact to swings and thrusts. Yes, I am aware physics is weeping, just go with it.]