glare at
睥 centers on a sharp, sideways look of contempt or defiance: glaring at someone with a sidelong glance.
睥 combines 目 (eye) with 卑, which likely contributes both sound and the idea of looking down or lowly, fitting a contemptuous glare.
The eye 目 on the left and 卑 (suggesting lowliness) on the right: imagine looking down on someone with a sidelong glare, treating them as inferior.
For ヘイ, picture glaring at someone and saying 'Hey!' with contempt: Hey -> ヘイ, and your eyes 目 show the glare.