Tunnel Fighting Under The Martian Surface - A Post Apocalyptic Mars - Stars Without Number Actual Play Adventure

The PC's have encountered a group of red men martian underground salvagers aboard a giant underground nuclear drilling machine. The players have elected to ride with these folks for a little while. Thing are about to get wild and wholly in the ancient Martian tunnel systems. They've entered Serpent men turf and are very near the edge of the Dark Martian territory.
These areas are the richest artifact fields and relic technology zones on the planet. There are also a boat load of serpent men underground temple structures, extensive military bases, and lots of weird technology below ground. The PC's are about to learn this as they are going to get embroiled in an all out war between two rival factions of red men underground cannibals and hybrid serpent people! 

There is a good chance that a Shoggoth might be released. Did mention that some shoggoths have psychic abilities in my campaigns? 

1d10 Random Weird Martian Underground Encounters 

1. A group of 1d6 heavily armed cannibal red men armed with heavy weapons including a bazooka or two along with small nuclear war heads 
2. A small mutant amoeba thing on its way to sleep after devouring a small village of mutant dwarf red men. Arms and hands can still be seen through the gelatin material. 4 hit points 1d4 damage, AC8 
3. An escaped Martian scientist whose quite insane but babbles in a strange mathematical language. Armed and will attack the nearest person murderously. 60% chance of having a very minor artifact on his person. 
4. A human serpent man slave dressed in nineteenth century rags and screaming his head off as he runs down the tunnels. 
5. A group of 1d6 serpent men 2nd level fighters armed with spears, short swords, and long poles tending a shoggoth and moving it to another temple. 
6. A gaggle of red men with brain in a jar leading them to a strange underground car that mysteriously just appeared. 50% chance the thing in the jar is a powerful wizard. 
7. An ancient robot that has recently awakened the poor thing is armed with a ray pistol and a bad attitude. It is looking for its owner and has no idea what has happened! 70% chance of knowing how any pre War relic technology works 
8. An escaped princess who claims to have escaped the serpent men's clutches but actually an assassin/psychic who is down in the tunnels hunting an escaped Martian royal. 
9. A gaggle of Serpentmen worshipers who are leading themselves to be sacrificed. They seem mind controlled but are actually high on Martian Lotus and may die at any moment. They're skin is discoloured and poisonous to touch. Save vs die or pass out from the drugs. 
10. A star spawn of Cthulhu recently summoned by the serpent men. Pissed off and very hungry.