Lex was extremely interested in the offer, which is what presented him with an issue. He was occupied with the forge right now, and he didn't want to distract himself from that. The Go board was increasingly becoming a liability he could no longer support. The way it could ruin things for him at the critical moment made it dangerous for him to take on any additional tasks.
Take, for example, the Defiler hunt. He needed a Defiler heart, but getting one was far from easy - as far as he knew. Lex had never personally come face to face with a Defiler, only the Profane, who were subjects or pawns of Defilers.
The only frame of reference he had for them was that almost any powerful civilization he had come across made it a point to eliminate all Defilers as quickly as possible. To adopt a mindset like that wherever they went, the Defilers were probably very dangerous. To take up a challenge like that with the threat of the Go board hanging over his head was asking for trouble.
