I hate having to worry about one-time scans. In one of the Phendrana Drifts rooms there's about four Ice Shriekbats that go kamikaze on you and if you don't scan one before they all die you'll never get another chance.
Also I went through everywhere again and still couldn't find the elusive missile expansion. Either I accidentally didn't save after picking one up that I thought I already had, or I got glitched.