I have been gving this some thought. If the engine exhaust does damage to the block behind it. You could easily set up an escape pod. Get a couple engines keymapped to a button with some blocks supporting the cockpit under them. You lose the ship, save yourself, and make it much harder to commandeer a ship with no cockpit. It will probably work best with utility ships like haulers or miners.
So, I guess, I would like an engine block that you can build right up to and causes damage. if you block the inlet the engine will pull O2 from reserves, similar to the UK's SABRE hybrid turbine/rocket engine