....
Eren felt relieved to find out that there was another connection to Earth. It wasn't even because he wanted to return to Earth.
He had long stopped craving for his life on earth, as life felt more distant than ever. The only reason he felt relieved to know that there was a connection to earth, was because he wanted to check on his real body at least once.
His soul had been summoned to this world. He still didn't know what happened to his body. If possible, he wanted to secure his body.
He didn't know what was going to happen to his soul if he was ever destroyed to the point that even his extra life wasn't enough.
If that happened, what was going to happen to his soul? Was it going to disperse into nothingness, or return to his main body?
If it was the former, there was nothing he could do. But if it was the latter, then he absolutely had to secure his real body.