The outstation failing would stop the mirror from working aswell, as it has the relays in it to drive the motors.
But if the windows work, then the outstation is OK - as it also drives that.
If you can't unlock the door then it probably is a case that the door latch is superlocked, and the sill button won't unlock it - you would need to either destroy to top of the latch or cut the locking hasp to get the door open, and then be able to get the door card off to access the latch.
'06 4.2 Supercharged Black/Cream "Jess" -- Bought April 2021 (NZ)
'01 4.6 Vogue Black/Lightstone "Snog" -- Bought Jan 2012
'99 4.6 HSE Cobar Blue/Lightstone -- Sold March 2009
'95 4.6 HSE Epsom Green/Tan -- Traded June 2008