**Given the fact submarines aren’t the fastest, how would anyone on a sub survive the deployment and underwater detonation of one of these torpedoes? It’d be a suicide mission wouldn’t it?**
You may be using old fashioned torpedo capability thinking.
These monsters are probably ‘smart’, and have a hundred mile range (or more?), maybe hold position for days (weeks or months?), then finish the job, or abort and return to ‘mother’.
Supposedly, they have a range of several thousand miles.
I would think that days / weeks on station would result in a a torpedo with no idea where it is. Undersea you navigate inertially and without a position fix from a star or satellite the accuracy of your inertial navigator degrades over time to the point where it's useless. Submarines address this problem with extremely accurate navigators that are large and complex, not something you'd put in a torpedo.
This suggests that such a torpedo would have to surface periodically to get fixes and / or communicate. And as such, would be vulnerable at least some of the time. Interesting thing to contemplate.