Andrew Fassbach: Mother Nature is a serial killer. She wants to get caught, she leaves bread crumbs, she leaves clues... Mother nature knows how to disguise her weakness as strength.
Jurgen Warmbrunn: Most people don't believe something can happen until it already has. That's not stupidity or weakness, that's just human nature.
Gerry Lane: If you can fight, fight. Be prepared for anything. Our war has just begun.
Chosen answer: The significance of showing the blood drop on Gerry's tongue and him spitting it out was to back up the theory that the only way to become a zombie is to be bitten by one. After the blood touched his tongue he ran to the edge of the building and waited 12 seconds (the time it takes to become a zombie) before he stepped off the ledge. If he would have started to change he was going to attempt to jump off the roof before causing harm to his family.
Then how does the scientist at the WHO get infected from a blood sample?
You can't turn by ingesting, or getting the blood on you. It has to enter your bloodstream. The scientist cut his hand and got zombie blood into his bloodstream.
He stuck himself with an infected needle or a "sharps" tool coated with infected fluids, which cut him.
Blood tester is encased in glass. Dr. Testing did not pay attention. His hand was in the case while it was mixing. Glass broke, cut him, testing blood mixed with his.