I actually do have one Mycroft/Jack pwp fic (Summoned). This one isn’t pwp though:
Mycroft Holmes was used to Jack Harkness acting strangely. Still, he was usually respectful of his personal space. “Why are you hugging me?” he asked, standing stiffly.
“There’s a sniper behind me and you’re the target,” Jack said in his ear.
Pulling away from the hug, Jack kept an arm slung tight around him, making a show of being his usual self while keeping the official tucked in close and protected. Jack escorted him from the plaza. There was the muffled sound of a silenced firearm in the distance. “And now you’re perfectly safe. Or at least as safe as you usually are.”
Mycroft gave him a bemused smile. “Thank you, Captain.”
“Anytime,” Jack winked at him and got the door of the black car pulling up to the kerb. “Keep your head down.”