I don't think there is a trophy for escaping with 4 people with a relic. But I escaped with 4 relics on solo. I used this setup:
All relics except the smaller wallet one, you'll need the cash.
You MUST use the DEATH MACHINE and be VERY ACCURATE!
Full auto pistol works just fine.
Body Armor to protect yourself from Rhinos or Swarms of Aliens. A total life saver.
Sentry Guns are highly recommended.
If you only run with 3 relics, then use the weapons specialist class for higher damage with your death machine.
Type of ammo: well it's your choice.
So when playing Solo, upgrade your death machine to max level as quick as possible. Be very accurate to conserve ammo and earn your cash back to continuously earn that death machine over and over again. Then upgrade your sentry to at least level 1. Then try to max out Body Armor to live much longer. You don't have to worry about Rhinos too much, that minigun will make short work of it.Then simply shoot your way out during your escape and TAA-DAA! You did it!
yes I have all the achievements, patches and backgrounds, I had a problem with the 5 relics because all the people I play with are still on the 360 and I am now on the XO, so to finish the 5 relics I had to find a lobby which would support me.
If your on either xbox you can add me, add Boy to the end of my username for my gamer tag