When Jeremiah looked down and saw that he was knee-deep in water there was panic plastered all over his face that didn't go unnoticed by everyone outside. It also didn't go unnoticed by his opponent Shelly so of course she capitalized on this and began her assault once more.
Shelly reeled back her arm and did a new attack that she hadn't done before and sent the trident sailing towards Jeremiah. Due to him being focused on the water he didn't have time to dodge but still moved as much as he could resulting in the trident hitting his arm that didn't have the sword.
When the trident hit Jeremiah's skeleton his body seemed to shake and he even took a few steps back due to the impact while he grimaced in pain. Despite being made of all skeleton, it seemed that he still received pain, which was quite interesting to Kaden as he wondered where the pain was registered from without any nerves in his body.