The Organians get their first good look at humans and wonder, now what do we do? As an observer only, they watch how Archer and gang react to a deadly silicon based virus. The purpose was to look for some reasoning type of intelligence as a precursor for eventual first contact. While possessing Reed and Mayweather for the majority of the time, they try to comprehend and understand why humans do the strange things that they do. The observational comments were a bit humorous during the show. The dialog between themselves about their own rules and protocols did shed a bit more information on Organians than what was first seen in TOS. It was interesting to see how at first they were just watchers, but as the story progressed towards the end they questioned their own believes to eventually save the day. Although not viral contagion, constant exposure to humans can contaminate ones thinking. 

During this crisis, Archer played his typical part as one who will do anything to save a crewmember. It's been quite obvious over the course of the series that Bakula really likes to play Archer. Bakula does this so well.

In the decon chamber, Trip and Hoshi contemplate their past lives by swapping life stories while coughing and vomiting. Viewers learn a bit more in depth of the backgrounds lives of these two characters. Trip makes reference to 'Andromeda Strain' as there were some parallels between this episode and the movie.

As a viewer, one would get the feeling that there was some real story-telling going on with the Organians.

1) Mayweather has a significant part in this episode, though not quite himself.

2) Hoshi gets lots of screen time, but has to die.

3) Hoshi once got kicked out of Starfleet.

4) Even thought Hoshi looked very sick and was dying, she still looked hot.