Summary: Everyone wears masks
John wears Colonel Sheppard like a mask, all rank and distance, ridiculously casual but always unattached. He wears his duty like a shroud, prepared to sacrifice himself so others never have to die for him.
Rodney's mask is him, with minor edits; it's ingenious. He talks and talks and rants and talks some more, focussing on his genius, his brain, his worth, his allergies.
He quantifies how they're going to die on any given day, spewing out the fine minutiae of his calculations.
No one ever tries to cut through all that bluster, pomp and ego to ask him how he really feels or what he really wants - they think they know. They've heard him talk for hours on food, on science, on blondes, on how he's going to win the Nobel Prize as soon as he can publish just a lone percentage point of what he knows. They think he has no secrets.
The more time John and Rodney spend together, the more naked they become. Masks slip and slide, eventually discarded. They see each other - they think they always have. These men beneath the masks were never strangers.
Their first 'thank God you're alive' kiss still surprises them.