Another useful "Emergency exit" is CTRL+Z which stops the process and cannot be intercepted.
It's often faster than hitting CTRL+C and waiting for process cleanup, especially when many resources are used. Then you can do e.g. `kill -9 $(jobs -p)` to kill the stopped tasks.
All of the keyboard-driven terminal signals can be intercepted; catching INT (^C) for cleanup is just more common than the others. Only KILL and STOP cannot be caught.
^Z sends TSTP (not STOP, though they have the same default behavior) to suspend; some programs catch this to do terminal state cleanup before re-raising it to accept the suspension. Catching it to do full backout doesn't make as much sense because the program anticipates being resumed.
^\ sends QUIT, which normally causes a core dump and is rarely caught. If you have core dumps disabled (via ulimit -c 0 or other system configuration) then you can often use it as a harder version of ^C; this is how I would tend to get out of ‘sl’ in places where I found it unwantedly installed.
For the most simple case of a single job, I use the job number (`[1]` in the example) with %-notation for the background jobs in kill (which is typically a shell builtin):
ctrl-z pauses the process, it doesn't terminate. I think of z as in zombie as you can then run fg to bring it back from paused state or as you suggested kill in it for good