Crack the line open again to pressurize the system. Listen for hissing. If it’s silent, you won. Pour yourself that carbonated whatever-you-wanted. I drank a seltzer so fizzy it made my eyes water, and I owned that burn. You’ve earned it.
And next time your roommate touches your tank unannounced? Hide the allen wrenches. Or better, teach them this same spiel. Sharing is caring, but only when you both know how to not create a fog machine indoors.