The fish doesn’t have to be swallowed whole....only the Sensor needs to be swallowed whole.
Correct and I suspect the slicing and tearing was done by other sharks at a relatively shallow depth. Once a chunk containing the tag was torn free, the feeding shark then headed for the relative safety of the deep to digest the meal.
Bingo. My thoughts. Orca kills it or bites off part with the sensor in it- it gets picked up by another opportunist and taken 2K down.