The minute the scrying crystal (which was really just a piece of resin shaped like a crystal, but Loki was loath to travel half way across the galaxy to steal one, when he could make one quite easily) pin pointed his intended target, Loki wasted no time in teleporting. He had been using the crystal for near enough half an hour over various parts of the map, having considered that S.H.I.E.L.D had the helicarrier so he couldn't dismiss the fact that they might not be in the general vicity. Also it was not an easy (or recommended) feat to teleport to a unknown location.
He appeared in a sparsely lit hallway, given the late hour and spotted the object of his villainous plot. The God of Mischief gave pause for a moment and considered how to play this, only to smirk and throw all forward thinking out of the window. He was bored and why not play with his prey a bit?
On silent feet (magic, of course~) he walked towards the doorway and slipped inside, pulling out a small silver dagger with his sigil engraved on its handle as he does; a gift from Odin on his name day many years ago and how he relished using them now for things other than heroism. As he thought on the heady joy this form of rebellion gave him, he crept up behind tired Agent. Long arms wound themselves around Coulsons neck in a horrific parody of a hug. Pale spider-like fingers pressing the blade to the mortals neck, which drew a pin prick of blood where it rested against pale skin.
"Hello Agent, have you missed me?" He whispered seductively into the other mans ear, lips pressed close enough to touch the shell of it as he spoke.