Later on you would learn that your rescuers,a extended family
of reptile-dragon folk who wheeled and dealed and traded stuff
with the planets they visited,had been planning to wheel and deal
with the passengers aboard the doomed bus.
Basically the alien traders had figured out that these particular
humans had been heading to a Dragon Con in town.
And since the traders to some extent looked like dragons,the Plan
had been to park their old spaceship along the route the bus
of potential human customers would pass by,keep the
Invisibility Shield on till the busload of customers came by
and then hawk the trinkets and souveniers the old
Delta Egg Cruzer had in her holds.
Obviously having the Acorn Doomstars show up and destroy
their customers hd not been in the Plan
so as soon as the reptilian traders had got you aboard
they were outta here.their so-so sensors already picking
up the rapid approach in space of the Alien
Squirrel Mothership,chalk full of nastiness....