Making new grenades wasn't an issue, and all he needed was just enough time to make more.
He kept pushing forward, and the enemies finally started to take him as a real threat. All of sudden, he started to face stronger enemies, a sign that much more formidable enemies were about to move and meet him.
"It's time to wait for others then," he knew his limits. Even if he grew stronger, he didn't think he could face high-end enemies right now.
A single one would be quite the headache for him. He was sure he could keep his life against him, but if more appeared, he wasn't sure about that.
So instead of pushing forward, he stopped, even retreated for a few kilometres while fighting the enemies he met.
The moment he did that, the enemy leader knew he wasn't going to keep pestering them. Yet the Nightmare monster tried its best to push everyone to send the high-end masters to take William down.