[dnanian]

I think you'll now be able to do this with a single line, since the mini-script worked, the tricky thing being escaping things properly, and I couldn't figure it out. So put the eject in a little saved script:

tell application "Finder" to eject "mjg"

save as text or a compiled script, and do:

#!/bin/sh
nohup /bin/bash -c "sleep 20; osascript path/to/the/script/file" &