You got confronted with a rat, the size of a lion to your perspective. It had a rather menacing look, and the ruffling of its grey fur is starting to get scary. Your instincts tell you to shoot that "thing", and you quickly obliged. You aimed at the rat with your AK-47, and fired a few shots. The loud sound of the rifle did scare the rat and took it aback for a while, but it looks like you have angered the beast, and it wants a piece of you.
You turned around, and started running as fast as your legs can go, with the rat in hot pursuit. During this time, you begin to regret firing those shots at the rat. You have not realised it, but the shrink ray had its positives. You start to realise that you have run quite far for your size, and you haven't felt tired yet. Even with the rifle in hand, you are not getting any weaker. The shrink ray, as it turns out, though it reduces your size to ridiculous proportions, but by doing so, much of the energy in the body is conserved as less energy is needed to do tasks.
Using your newfound "powers" you stopped to confront the rat, which is getting very close, with that same menacing look in its face. As the distance between you two get closer, you grab on the rat's ears, and with one single action, you lifted it up high in the air and threw it back down. The rat fainted from that move of yours, but you are not taking any chances, as you reached for your rifle and finished the job. The rat is finished, but you are not staying here, especially if there is a rat colony around here. Taking your rifle with you, you ran away.
You kept running and running until you have finally exhausted all your energy. As you panted and gasped for breath, you dropped your rifle in exhaustion, and fainted. What happens next?