Lennox is no medic; he is no mechanic.
He never has been, never wanted to be, before he got into the Army. But when his squad took fire, before or after NEST was established, he was always there, jumping into action- holding a soldier’s wound closed and screaming for a medic, murmuring soft comforts into a soldier’s ear even as he screamed for his mother, for water, for mercy.
So after NEST is established, it’s immediately natural that he dives for a bot when he sees a large splash of energon, hears him hit the ground. Silver plating- not Ironhide, which he hates brings comfort to his chest, the same comfort when it’s not Epps- is wet under his hands, and he hasn’t got a mechanic’s kit, hasn’t got anything to block off that line-
He grabs the ruptured line with his hands, holds it together, even as his voice raises in a sharp cry for Ratchet, his comms broadcasting his shout and pinging back Ratchet’s affirmative. His hands are there, clutching that line for dear life, and he huddles down, against Sideswipe’s frame to avoid gunfire, promising the silver mech that he’ll be okay, that Ratchet will be there soon, and the bot grumbles, something about how he doesn’t need some squishy reassuring him.
Lennox has been around the bots enough to know that when they’re scared, their plating fluffs up, and like a human, their fuel pump rate increases. He hears Sideswipe’s denial, feels his truth under his hands in the speed of hot lifeblood.
Ratchet arrives, as he always does, and he’s not too gentle as he moves Lennox aside, into the arms of a human medic. Her eyes are wide with alarm- he wonders, for a moment, if this is her first assignment, though a scar through her lip says otherwise, dancing as she speaks- “Major- your hands.”
Usually, the humans didn’t touch Energon. The engineers working with the Autobots were always so careful, and he’d never considered the damage that their lifeblood could do to organic material. He assumes, then, that he’d managed to catch his hand on some sharp edge on Sideswipe’s armor, but as his gaze follows the medic’s, all he can do is stare at the welts, raised and angry, from where Energon had splashed through the hole he’d been forcing shut.
“Oh,” he says. What else can he say? The medic pulls him down, to the ground, and pulls a bottle of water from her pack. The wound is rinsed, first, and tightly wrapped with gauze, but when he reaches for his gun, a sharp snarl of his title stops him, the medic’s hand firm on his shoulder. “They need me,” a protest, a statement, as she grips him, pulls him back towards command.
Her reply is tense, sharp. “You need medical attention.” The tone invites no debate, so Lennox brings none, lets her pull him up, and offers a terse nod to Epps. A quick nod in response, and he’s shouting orders.
He finds out later that these were chemical burns; a few months of treatment, and they fade from welts to scabs to scars, as burns tend to do. The doctors lecture him on the dangers of Energon, on why he should avoid holding lines closed without protective gear- Epps does, too, even as he knows, deep down inside, that Lennox won’t listen.
The scars layer and multiply.