Blood was all around the entrances to the Israelites' homes. There was a death at the entrance. Death was not allowed inside. Like the story of Genesis, death could not enter the Garden. Death's domain is outside the Garden.
Death can go anywhere it pleases, but one place and one place only.
Death could not enter the Garden. Graves would only be found outside the Garden. God sent Adam out to one day die in the dust outside the Garden from which He originally took man from. Beyond the Garden entrance is eternal life. A tree of life with fruit giving eternal life to the eater.