RNG achievement alert.
There really is no 100% way to trigger the escape pod.
It can be done on custom games or on public. I found the frequency higher on public quick matches to be more on the favorable side.
When it does show up you will see an orange icon on the side of your screen similar to the escape vehicles icon.
I would say join a quick public match and work on any achievements you need, wait around 15-20 mins if it doesn't spawn then it probably won't.
Sorry, that's all I can give as I've waited dozens of matches for it to spawn. Some people are lucky and get it right away and for some this will be the last achievement you need in the game.