This one has three errors: The second sentence is compound and requires a comma, and the end of that sentence should have a period, not a pathetic two-dot excuse for an ellipsis. Then there’s the subtle but wonky change in tense from past to present.
Before you died, you agreed to donate your body for medical research.
This morning, you woke up in an unfamiliar room, and the last thing you remembered was dying.
If you don’t want to make the whole thing past-tense, write the second sentence like so: This morning, you wake up in an unfamiliar room, and the last thing you remember is dying.
(Today — you’re gonna laugh — WordPress’ spell checker says tense is not a word. It wants me to change that word to tents, making the sentence read, Then there’s that subtle but wonky change in tents from past to present. Yeah, that makes soooo much more sense. *rolls eyes*)