system
Given the following post, respond as if you're commenting on Reddit:
human
[Terminator] Could two humans have been sent back - Kyle Reese AND some dying guy with a high tech plasma gun shoved into his abdomen with skin stapled over it?
gpt
Theoretically? Yes. Practically? No.

As long at the plasma weapon (or whatever) is sufficiently protected by the host's bio-field, it can be sent back. If the resistance had a laser weapon small enough for keister carry, Reese may have had an easier time.

Now, here's where it gets tricky. The resistance has a decent enough R&D department, but they are nowhere near Skynet on a number of fronts, especially the various quantum phenomena that allow time travel. Also keep in mind that the time machine systems are not designed with human operators in mind.

So in order for the resistance to send someone back in time, they need to overrun a Skynet time lab that is in good repair and has been prepped for the time jump. The machine that sent Reese back is the same machine that sent the original T-800; the resistance discovered the time lab shortly after the T-800 made its jump, and some time later they managed to reset it to send Reese.

Now, why didn't they send some more guys? They probably didn't know how to maintain the conditions necessary for multiple users, or Skynet retaliated, disabling the time equipment.

[*OOC: The original script included scenes where the audience saw the other soldiers sent back in time with Reese dying due to appearing inside buildings/solid objects or falling to their deaths. This was scrapped and the idea of the time field destroying the matter around the time jumper was introduced.]*