Widespread mention over "Pontypandyness Monster" again, even if it doesn't exist. Remember the time Sarah made up seeing it in order to help her grandad Gareth and his train.
Some laughs like Norman had false alarm when he excitement in seeing the sea monster is in fact Joe Sparkes and his submarine thing. Again, Norman makes the dangerous idea of stealing it and going underwater alone in it. Then from bad to worse, controls messed up that he has the submarine submerged on the lake floor and water seeping in.
Surely, he could've clogged the leak cracks on the window.
I have to admit that Ellie was too harsh on Elvis (he's got fame seeking personality he has) in this episode - she telling him he's hogging the spotlight with his floppy shovel than Penny. Surely Penny rightly tells Ellie that it doesn't matter and their jobs as firefighters dealing with the emergency.
With Sam having use of Norman's camcorder, Penny has a moment on the TV mainly underwater rescue in diving wear. Just as I've seen in "Bake Off" special, Penny is definitely has stage fright or camera shy like.