the mirror is reflecting the light emitted by the lamp better than a wall will do.
Will it? Maybe. You are making the assumption that specular reflection is better at reflecting than diffuse reflection, but that is a false assumption. It depends on the reflectivity of the wall and the mirror. A white wall can reflect more light than a mirror.
No, he didn't. Other people, who had absolutely no say in what Biden would do, said he wouldn't run again.
https://thehill.com/homenews/campaign/474059-biden-campaign-denies-one-term-report/