You can check how much cpu/memory processes use with the 'top' command. It would be better if there would be some mechanism that warns for backgound processes taking up too much resources. I'm using the Powerlaunch app to put the device into 'softpoweroff' (sleep) mode as alternative to 'lock screen and keys'. I'm not sure if this is 'suspend to ram' but if it is then any runaway processes should be paused as well.