Release method of an CO2 cannister using only 5v?

Hi,
Im trying to figure out how to release a cannister of CO2 or NO2 by pushing the canister nozzle into a spike. Space is a premium, the smaller the better. If all fails I'll need to use a central door lock mechanism from a car (big and over 5v). Im really rookie with the electronics and iv bitten off a huge project that I need to finish.
Would love an idea like using a solenoid to release a strong spring is some form but I cannot think of it.

Help would greatly be appreciated.
End use is in a sea water environment.

Direct-acting solenoids cannot produce much force, certainly not without using tens or hundreds of amps.

You need something with gears. All the car door lock actuators that I've ever opened had gears. But the door lock actuator is only supposed to push about as hard as a person can with 1 finger. Can you operate the CO2 cartridge with 1 finger?

I would look at making some fine-pitched screw turn with a motor. Use a worm-drive gear on the motor so that the screw turns slowly, like 5-10RPM. With only 5V available (you didn't say how much current but I'm guessing a normal USB port's 500mA) this will take several seconds to clamp down on the cartridge.

Remember power is the "rate of doing work". You have a lot of work to do (breaking the seal). With only low power, you can only do it slowly. If you have to do it fast then you need more voltage or more current or both.

Long lever might make things easier - might even be able to use a servo then, but without
knowing the force required, its all guesswork - have you measured the force needed to pierce the cap?