后送医院

• 口(mouth; door)RADICAL
• 后(behind; empress (figuratively—one who rules from behind))ASSOCIATIVE

A mouth giving orders from behind the golden throne is the authority of an empress.

• 辶(step; move)RADICAL
• 关(related; closed)PHONETIC

Seeing someone off is the step of walking together with a loved one all the way to the place of parting.

• 阝(earth mound; fortification wall)RADICAL
• 完(complete; whole)PHONO-SEMANTIC

A school campus surrounded by sturdy and complete walls forms an enclosed institution.