Medical Assistant
Medical Assistants were essentially Staff Assistants with built in access to Medbay. Medbay tends to have so much traffic that it is not hard to walk in to begin with, so this is often not that big of a deal. Nominally, the job involved following around the Medical Doctor and helping him with triage, or working alongside a Roboticist or Geneticist while they do whatever it is they do. This made it a great job for a new player - simply ask someone if they could show you how to do their job, and they will often happily do so.
In practice, however, assistants are often skilled players who joined too late to get any other job. Without more productive work, these skilled players quickly get bored and resort to hooliganism, harassing anyone they come across and physically assaulting anyone who doesn't look like they're paying attention.
Crew Objectives
As a medical assistant, you could expect to see the following:
End the round in perfect health
Just have 100 health. The simplest way to do this was to pump yourself with medicine near the end of the round, and if you were heading to the escape shuttle, hop into one of the sleepers for good measure.
Ensure the Head Surgeon gets off the station alive
The Head Surgeon started in Medbay and just had to be pulled onto the escape shuttle.
RIP
Sadly, the shuttle containing this shift's technical and medical assistants crashed. Into the moon. Forever.