[受「う」]け[身「み」] => Passive, be V-ed. N4
Causative, Passive, Volitional
中 => Throughout, all over, during the course of N5
Time
[使「し」][役「えき」][受「う」]け[身「み」] => Imperative N4
Causative, Passive, Volitional
[最中「さいちゅう」] => In the middle of A N3
Time, Situation
[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous