Specific Details Please
If the solenoids are buzzing/humming when you pull out the timer, but no water is connected; well they would wouldn't they? The thing or things are calling for water but none is coming.
Should these sounds come from any where timer is pointed that requires machine to fill with water, and you've pulled out said device (started machine/energized solenoid), but you've disconnected water, again the valves are dead or going.
One small mercy for you is that the washer in question is portable and not (assuming) permanently connected to water. People have flooded out their laundry areas/homes thanks to a stuck solenoid in washing machine.
Simply put regardless of the timer being at an "off" position or not, long as there is electric power to the machine solenoid (if faulty and stuck in "open") will continue to allow water into tub. Just like a sink or tub when taps are left running, a top loader (or even some dishwashers) will continue to fill under such circumstances with water having to go *somewhere*.
Many modern dishwashers and front loading washing machines have *water control systems* designed to (among other things) shut/block off water in hose from the tap when leaking/excess water situation is detected.