That depends on the writer, I would say.
Mainly I answer this to my fellow SG member when they ask why I do not teleport them in my story, and instead leave to bleeding and suffering all over the chapters.
The story I write is game based, not game ruled. 
Yes, but I'm wondering about how other players/writers use the component.
It's part of the story I'm writing, so I guess I'm just looking for a consensus.
Shyft - Gravity/Kinetics Controller - Virtue and Pinnacle - write up at virtueverse
Vigilant Eye - Sword/Shield Scrapper - Virtue - write up at virtueverse
October Star - Energy/Energy Blaster - Pinnacle
and a bunch of alts....
I use it as a belt accessory on some and as a simple push button integrated into the costume on others. It really is up to you. There are many many options. Try not to limit yourself by others ideas.
Start a level 1 character and go through the tutorial. The first "mission" is to deliver the sample to the doctor outside the hospital who then tells you to read the info display. The info display tells you all about how the mediporters work. They work off a patch the heroes wear, that registers when their vitals indicate they are about to die. That activates the teleportation sequence that takes them to the nearest hospital.
In terms of RP, I'd say that's good enough. In terms of stories, since its a patch I'd say it can get or be removed and in either case it could be damaged/destroyed in a fight.
In some RP stories, some authors tie it to the Hero ID, some as a patch, some as a gadget in the belt, some as woven into the suit, some as an implantable bio-chip.
Possibilities are limited only by your imagination.
And just to add some side info that I thought was interesting -
There are large structures that are essential to the functionality of the medivac teleportation; one of them is in the South West side of Skyway City. I dont know where others are.
In a Hollows mission against the Circle of Thorn the devices didnt work; when you selected to go to the hospital you ended up in a holding cell (interestingly enough you were healed).
Question:
How do you or your supergroup RP the hospital teleportation? Is it a chip implanted that they home in on? Is it the equivilant of a "Med-Alert" Bracelet? Is there an "official" stance on what it is? Just curious for a piece I'm working on.
Shyft - Gravity/Kinetics Controller - Virtue and Pinnacle - write up at virtueverse
Vigilant Eye - Sword/Shield Scrapper - Virtue - write up at virtueverse
October Star - Energy/Energy Blaster - Pinnacle
and a bunch of alts....