Looking at the temperature/pressure chart on the Wikipedia page (https://en.wikipedia.org/wiki/Pressure_cooking) any plant or animal tissue, perhaps even bone, would maybe be reduced to a thin sludge long before reaching 400F.
The Wikipedia page mentions pressure ovens, though, which seem designed to achieve the effect you're looking for--fast cooking with browning (Maillard reaction). Personally, this is why I love the Kuhn Rikon fry pan pressure cooker. It has a tri-ply, dimpled bottom for excellent browning; then you can just deglaze, add remaining ingredients, and slap a lid on for pressure cooking. It only holds 2.5L, though, so in practice limited to dishes of about 8-10 servings at the very most (typically more like 4-8 servings).
The Wikipedia page mentions pressure ovens, though, which seem designed to achieve the effect you're looking for--fast cooking with browning (Maillard reaction). Personally, this is why I love the Kuhn Rikon fry pan pressure cooker. It has a tri-ply, dimpled bottom for excellent browning; then you can just deglaze, add remaining ingredients, and slap a lid on for pressure cooking. It only holds 2.5L, though, so in practice limited to dishes of about 8-10 servings at the very most (typically more like 4-8 servings).