Well, I've fallen victim of this too, although the only way of getting the passenger door open is with the internal mechanism.
It's happened before, but after a decent long blast to recharge her batteries, it has cleared, not today, not playing says she.
Mind, it's probably because I've neglected her for a week or so, the battery certainly sounded sluggish on start up, dashed tracker drain, combined with having left out on our forecourt/driveway until I can clear the garage of removal garbage from our recent house move.
I'll put her on an MX5 recondition cycle tomorrow to see if that clears it. Strangely, the window detent usually plays up before anything else, but seems OK.
On other cars, it's been possible to spray WD40 or electrical cleaner into the lock mechanism without having to remove the inner panel. It was too dark tonight to see if its possible.
However, the symptoms seem strange: no solenoid sound as usual when voltage low, but tried the external manual lever next to the microswitch handle/catch for the first time. Very very stiff, as is the driver's side too. Manual opening has probably never been exercised.
Any advice on squirting fluids/repelants down suitable orifices would be gratefully received. Not sure that the mechanism is truly bu%%ered yet since it has burst back into life on full battery. It'd be good to free up lazy/seized mechanism though