@RubyMineshaft, bold of you to assume I would stoop so low as an Agatha Christie villain (loved those 'Advanced History of other Civilizations" lessons, so entertaining).
Since it’s come to this, let’s talk business: I have an important mission with the highest clearance and I need one more night to send all the data to my superiors.
So, I will offer all of you a trade: don’t kill me today, and I will reveal one of my team to you. You’ll only lose your other bodyguard, and they signed up for it. (You don’t really mind killing innocents anyway, do you? Looking at you, Colonel Jessup.)
You might think I’m lying and won’t keep my promise, but keep in mind that, unless your detective is very lucky tonight, you’ll probably kill another innocent tomorrow.
This might be a team effort, but I was chosen for this mission because I am not a team player. MY mission comes first. As you know, I don’t mind my comrades getting little “accidents”, if they get in the way of what I want.
Or maybe my own partners will kill me tonight, to save their skin. They do put the team mission first (drill instructor choices, no vision 
). You get one night for free, with no abduction and your detective can do his sleuthing uninterrupted.
Keep in mind the only times I wasn’t completely honest were the sun flares (which honestly I didn’t think a bunch of mediocre earthlings would pay attention to a throwaway excuse, I had to send my data without alerting the other two mimics) and hiding my true identity. Otherwise, I have worked towards killing as few humans as possible.
Just so you know, bloodthirsty basic life forms, all your missing astronauts are safe and sound. Some have already seen the light and are cooperating with us and some are in stasis. The only dead human died in your hands.
P.S. This is not a negotiation. Take it or leave it.