So the distance between milky way and andromeda is 2.537 million light years or 780 kiloparsecs from earth give or take. With FTL travel it will take approximately from earth 2.54 million years to reach, now from let's say our ark inhabitants perspective it would seem much shorter of a distance. Now with FTL the aging process would be slower amongst other things(Neil degrassee tyson speaks about this) but even so several lifetimes onboard the ark would have had to transpire. Meaning as with me1 upon starting a new game you can choose your background, what is the history aboard the ark? What background history will they have? Spacer, spacer or spacer? What monumental triumph led you on the path of greatness? There's no akuze so what, you stopped cerberus from taking over the ark? Joined the a-sec? Some krogan saw a space fish and decided to space walk in attempt to eat it but you saved him and the ship from certain doom?
How exactly do you think they approach this or will they just go "uuuh, space magic, yeah space magic."? Depending on the background you chose upon starting a new game the dialogue and how people saw you varied.

I'm genuinely interested in how they will approach this