There are a couple of different ways to do realtime tape stop effects using the Tensor.
Tape stop using momentary on
Set SPEED to 50% so that the sound is stopped. Set TIME and PITCH to 50%, since we want it to be stopped or normal playback. Set BLEND to 100% so that we hear nothing when it is stopped. Set RAND to 0%.
Set the ON footswitch mode to M (momentary). The Tensor will be in bypass by default. When you press and hold the ON footswitch, it will quickly stop the sound like a reel-to-reel tape deck or turntable. Releasing the footswitch will start the live sound again.
We are not using looping, but you can set the HOLD footswitch mode to M (momentary), HOLD to REC and DIR to FWD. Tap the HOLD footswitch briefly to grab and repeat part of a note, or tap it (poly)rhythmically to skip and stutter through your notes. You can also hold it down for an odd note length (like 5/16 note) to get a very playable broken recorder sound.
Tape stop using expression pedal
Use the same settings as above, but set the ON footswitch mode to L (latching). Plug in an expression pedal with the default setting (no knob assignments). By default, the expression pedal morphs from normal playback (heel) to the knob settings (toe). Start with the Tensor on and the expression pedal in the heel position.
To stop the sound, push the expression pedal quickly to the toe down (maximum) position. Then, as you are playing, slowly bring it back to the heel (minimum position). The live sound will slowly speed up. You can adjust the stop and start speeds to match your playing.
Random tricks
If playback is stopped (SPEED=50%), the RAND control is still active. Crank it up and the Tensor will spit out sputtering notes. You can adjust PITCH to have it jump between set pitches, or leave it at 50%
Trivia
The Tensor's start/stop torque setting is based on Curt's SL-1200 MK3D. So technically it is a turntable stop effect. The torque is adjustable internally, but as of version 1.2.2 it is not user accessible (yet).