wrong journal but...! an I idea I had was that Crane could intervene in the aftermath of the Syrlya vs Howl and Barnaby fight. Howl will be dissipated and Syrlya will get away, and Barnaby will be enraged/devastated that he wasn't able to protect Howl and will be determined to track Syrlya down.

Maybe Crane could find him while he's basically still in this feral revenge-focused state of mind and get him to cool down, advising him that getting Howl's shard to safety is the priority? It would be a good incentive for Barnaby to feel indebted to him later, because not only would he stop Barnaby rushing off and getting himself killed, but he'd be indirectly looking out for Howl as well.

I don't have any plans for Barnaby to participate in the boss fight either, so it could be a good opportunity for them to retreat together, timing-wise.