bear boss sylvan dungeon - exploit + what on earth was I supposed to even do???????

There was a caged 1x2 room I was able to lure the bear that can heal himself into... I lured it in and spammed attacks until it died as it couldn't escape. I had an AI parter that also helped block it from leaving.

The bear went to heal itself so I was looking around for a way to defeat it (idk how to kill it the vanilla way. I had the potions to cure the diseases with me too. The trees were immune to my level 37 axe.) As I looked around. I noticed there was a cage I could hide in that the bear didn't seem to be able to fit into.... IT INDEED FIT INSIDE AND GOT STUCK WITH ME. I spammed potions and blocking untill I got out and proceeded to kill the bear the way it deserved to be killed.

For extra context: This is the boss bear you have to defeat in order to proceed to the next campaign realm.