Back in the cell that Dyra and Yill put him in after they kidnapped him and the cats, Toz hadn't had any outside interference when he melted the cell walls. He had been allowed to completely block out everything else and freely sink into his fire magic using his mana vision.
But now, Toz was in a much larger room. One that wasn't cut off from the rest of the world. There were also boatloads of enemies trying to attack him with their weapons or with magic that he didn't know how it worked. The conditions were far less optimal than they had been in his cell.
However, Toz had after he broke out of his cell. His understanding of fire had deepened, his mana had reached a new level, and his mind and mana vision had improved and grown stronger.
There was also the fact that Toz was more desperate in his current situation. Although he desperately wanted to get out of his cell back then, he wasn't in a position where he would absolutely end up dead if he failed.
