Jenny Pinter is pretty much the first to know everything. There's something intimate about her job that makes people more prone to spill their secrets. On Earth, it always amazed her that more people would confess things to her than they would to their shrink or their priest. Once she joined the Marines, she thought it would be different. But, weirdly enough, a posting announcement came out that was looking specifically for soldiers with multiple skills, and being both a communications technician and a trained hairdresser came in really, really handy.
Dr. Beckett and Lt. Cadman are having problems, and Jenny's heard it from both sides. When Dr. Weir got over Simon, Jenny was the first to know, and she happily shaped Elizabeth's "mom hair" into something a little breezier. She'd give real money to give Zelenka a trim or snip that greasy ponytail right of the back of Kavanagh's head. Jenny dislikes the red on Dr. Heightmeyer and will change it back any time the good doctor says the word.
She knows exactly when things get serious between Dr. McKay and Colonel Sheppard, because Sheppard accompanies McKay to her for his every-five-weeks haircut and watches her like a hawk. Jenny trims Sheppard's hair precisely every seventeen days. It took them a few months to work out the optimum interval, but seventeen days is the magic timeframe that lets him look like he never gets a haircut. She knows every psychotic cowlick on his head, knows exactly how thick that mop of his is. She's spent no small amount of time imagining what it would look like if he grew it out. It would be floppy, she thinks, and it would take 10 years off of him in an instant.
She knew when Sheppard and McKay started up - she saw the hickey when she shampood the Colonel's hair, and she allowed herself to be sworn to secrecy. Sheppard's not a big talker, but Jenny got a tidbit of information here and there. It's weird, the two of them, but she was content to see Sheppard relax a little. McKay, however, was as tense as ever. At least, until things got serious.
Now, Sheppard comes in with McKay, and he mock-threatens Jenny with field work should she give McKay an uneven cut or nick his ear. McKay protests that she's irreplaceable, and that he'll fight Sheppard tooth and nail to keep Jenny on base. They banter and play, and it makes Jenny smile to see that they're happy.
She figures that the day McKay gets invited to observe one of Sheppard's haircuts will pretty much be a proposal.