You bury things into people who look like they've died. It's called implantation. They're not really dead though. This is surgery and they'll wake up and go about their lives with whatever that thing was that you put in them.

This is a jukugo word that uses the on'yomi readings of the kanji. You didn't learn this reading for 埋 yet, so here's a mnemonic to help you:

Wait that's not a person you're embedding things into. It's a bunch of mice (まい). I guess that's okay. Just don't go putting the mice into people. That's... don't cross that line.