My reaction would be the same as any other bioscientist: to check whether their alien physiology are affected by chloroform the same way we are. Because as we all know, bioscientists totally carry chloroform with them in their back pockets at all times in case of aliens, rapists or tigers that escaped from the zoo.
If it works as it does on us, I'd bring them to one of the labs at my university and take some samples before the person wakes up, and later experiment like all hell on those samples. If the person in question asks what happened when it regains consciousness, I'll tell him that next time, he should be more careful around banana peels, and that I figured that the lab was the best place for him to rest.
If he's an alien: bam, instant Nobel price. And presumably some alien MIBs knocking on my door at some point, but I know karate, and I still have my chloroform, so fuck them. MORE SPECIMENS.
If he's not an alien, then it's a good thing he just tripped on a banana peel.
If chloroform doesn't work, I'll get excited as all hell and ask him about how that works. Hopefully he'll answer, after he's punched me in the face. And then I'll use that knowledge to gain a greater understanding of life, and hopefully to speed up my human extermination virus.