don't move the plunger, remember, the ink falls due to gravity, not the plunger pressure
The reason I was wondering is that I've observed that the bubble in my converter stays put, no matter the orientation--unless I flick it like doctors do with a syringe. It's like the reservoir is so narrow, and the mass of ink is so tiny, the surface tension is keeping the ink from flowing around the bubble. Not that I've really had a lot
of problems writing as a result, except when I'm very close to running out of ink. It's at this time that I notice the pen starting to write more dryly then normal, and if I take the pen apart, there are maybe 2 or 3mm of ink trapped behind a large bubble of air. If I didn't have my ink bottle handy, are you saying that I should just put the pen aside in this situation? Am I inviting trouble* if I push the air out? While I understand that unsteady hands could lead to a mess, but am I in danger of doing damage to my pen or getting a ink blot where I meant to sign my name?
* I know I could end up with ink spurting out when I do this, but if I'm careful, are there other issues, like the ink flowing to quickly through the nib, or clogs... that kind of problem.