[The drugs could cause memory loss if there's extended use? Dojima wonders...]

If the extended use of those drugs can cause memory loss, could it be possible we have been here for longer than just a few days, being subjected to those drugs?

That'd explain why so many of us lack part of our memories.

[No, wait...there's one flaw here. Dojima shakes his head]

On second thought, that's unlikely. it'd be very convenient for everyone to lose the same memories - the part about being here for a long while.