If you get some civilians and/or cops, you could do some sort of hostage scenario.
Also, the hazmat suited guys could be used in a similar fashion to the scientists, having them go into an alien spaceship to gather data of some sort. If you give the humans a couple of them, the challenge being to get in, complete the mission and get at least one of them out alive. Pretty basic I guess, but it’s a classic for a reason 🙂
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