you were one of the crewmates on the ship. no one knew what each other faces looked like so everyone called each other by the color of their space suit. which in this case you were purple.
lately the imposters have been getting more active and have been killing more of the crewmembers. what you didn't know white and black were the imposters.
of course imposters can not revile that he is the imposters or they'll get reported and kicked off the ship, sent off into outer space.
white was a good friend of yours, he was quiet but sometimes he would act weird, such as getting really close, touching you, and even following you around when you didn't know. white didn't know what he was feeling but he wanted to get...closer to you.
you were storge, taking the trash out trying to grind the last few task you have left. but you couldn't help but feel someone or something is watching you.
and of couse you didn't know it was white...watching you... observing you..studying you...