Ryan considered his options in that situation. Changing the direction of his attack won't change anything. Even if he tries to attack the Chupacabras from behind, it won't work. The bosses were hidden, and most likely, they were behind their minions in case Ryan decides to do that. So, by doing that, he will avoid the army of monsters for a few minutes. However, the chances of him defeating hundreds of bosses in such a short time were null.
"Power of Money won't be of much use here either since it will reveal my position. As for magic traps… it might slow them down a little bit, but only that. Besides, I can't waste time creating thousands of those."