Here's some random thoughts. Hope no one minds.

"Lion's Den" reminds me of the biblical story "Daniel and the lions den". Lions don't attack Daniel in the story. So maybe Saul goes back in to the zombie-hole (with a bomb or just to recon) sometime before this chapter ends. Makes sense to me.

Also who is smart enough to deduce the ultimate cause of the outbreak? The only person I can think of is maybe Ink (maybe via a journal or notes). So there is a chance that the root cause of the zombies is one of the mysteries that's left at the end. But Ink's actions looks like they'll be fully explained.

Ink...A Story of Survival.