your tags just hit me that shiro really did give up ulaz’s sacrifice on some level just to keep keith safe and alive and away from the bom and their trials. that even after shiro felt so strongly about ulaz and what he did, how he’s helped shiro before shiro even knew who he was, shiro still decided an alliance wasn’t worth it. everyone quotes that “nothing was worth shiro’s pain” (which is true to keith’s character!), but i think nothing was worth keith’s pain, too, in shiro’s mind.
god ok not to get all sappy and stuff but seriously, shiro values keith on a personal level that we don’t see with anyone else or between any other two characters (except zarkon and haggar lbr). like ulaz is the one who saved shiro’s life twice and i think shiro takes that kind of sacrifice really seriously. he guns for that alliance with the blade of marmora for the entire second season. he goes against allura and the rest of the team to fight for it.
…and then keith wants to keep his knife. that’s literally all it takes. anyone who says there’s a power imbalance between keith and shiro or that they don’t explicitly and unconditionally trust and love each other needs to rewatch this episode. shiro could easily order keith to give it up, downplay the knife’s importance, or at least argue that an alliance is more important than the knife, but he doesn’t. he literally takes one look at keith and calls it off entirely.