ok i've turned to scripting all the models to board the dropship - this takes three minutes! It's worked but after about 5 scripts fire the game crashes
It's either the number of scripts running or the number of models in the same area - all the models move to the same spot and then become invisible and non-solid. There must be 30 npcs in the same spot but invisible and non-solid so there must be some kinda engine mess up.
I shall try moving the models away from this spot but this could apply to someone else so i think theres a limit to how many models can be in one spot even though they're non-solid.