Lin Wenwen believed that Lu Tong deserved a heavier punishment. However, it was Yuan Tianxing's decision to make, and not hers. Nevertheless, it would be really hard for Lu Tong to survive the world of zombies, as he was only a space possessor.
Yuan Tianxing, of course, didn't plan to let him live. Without the base's protection, Lu Tong had no chance to keep himself from being torn into pieces and eaten by zombies on his own.
His decision was like a death penalty for Lu Tong. If the latter was lucky enough, he might be saved by some zombie hunters. However, the hunters near All Beings Base were all from the base. Even if they saved him, they wouldn't be able to bring him back into the base. The only way to save him for good was to send him to Sea City Base.
That kind of chance was too small to be counted on.