Toss the shrimp in 1 tablespoon olive oil. Season with a good pinch each of salt, pepper, and seafood seasoning. Set aside.
Heat a large nonstick skillet on medium-high heat. Add the shrimp and cook until very lightly pink on one side, flip, and cook until very lightly pink on the other. Remove from heat and transfer the shrimp to a dish. Set aside (shrimp will still be raw in the middle).
In the same skillet, heat the remaining 2 tablespoons olive oil on medium-high heat. Add the mushrooms and saute, tossing occasionally, until softened and a little brown. Remove from heat.
In a large saucepan on medium-high heat, heat the butter and flour. Whisk until smooth. Cook a couple minutes, stirring regularly, to make a roux. Whisking constantly, slowly add the half-and-half. Cook, stirring constantly, on medium-high heat until mixture thickens to the consistency of gravy.
Remove from the heat, and stir in the shrimp, mushroom, and corn (the shrimp will finish cooking in the sauce). Add the seafood seasoning, salt, and pepper.
To serve, gently fork split the biscuits, spoon gravy over the bottom biscuit half, and top with the top biscuit half. Spoon a little more gravy over top, and garnish with green onion and bacon crumbles.