Thinking about how Thjazi not breaking the glyph was a snap decision. He didn't plan his own execution in advance as part of a masterstroke play, based on how he was joking with Hal he clearly expected to escape using the glyph. And then he saw that falcon, presumably Mara the Wing. Others have mentioned that he likely chose to die because what he was doing with the blood from the River Gavzidra required someone be in the Tenebral Reaches, and him seeing Mara signaled to him that her passage had been blocked, and he realized he had an express if one way ticket to exactly where his plans needed someone to be. So Thjazi chose to allow his own execution to proceed, and rushed out his last words to Hal in the scant few seconds he had. Circumstances very suddenly required him to willingly sacrifice himself for his cause, and he made that choice very decisively even as he was clearly scared to die. Thjazi was certainly a lot of things, but one of those things was that he was a man who was willing to give up everything if it meant living out his ideals.











