I can imagine that Danny was embarrassed about admitting he had claustrophobia and didn't want people to think he couldn't do his job.I don't suffer from that phobia but I went snorkeling once and just could
not put a mask over my face.That's the only time I've ever felt that panicked so I assume that Danny has avoided getting himself near small spaces during his career.I have a feeling that claustrophobia might come up again in the future
The case was convoluted but not unusually so for a Hallowe'en episode.I don't mind Max but sometimes I have trouble understanding his dialogue--a bit like Steve, Danny & Chin whenever they have to go to the ME's office.
The chase at the end was enjoyable for me because I've been on that road

The bunker where Brock was being held is usually filled with props from Jurassic Park, LOST and other films/TV shows.It was used in the first series, too.It's a great drive.
I'm really enjoying Season 4 so far