Kirk got off the bridge somehow in "Wink of an Eye." And Khan said he "jammed up [their] exit routes." Note the plural.
Firstly, the Scalosians opened all the doors of the Enterprise, including the turbolift doors, so that they could move freely throughout the ship without waiting for the relatively slow doors and turbolifts to activate. I followed the bridge scene in
Wink..., and after Kirk in accelerated, he leaves off the bridge by going into the turbolift and moves toward its port side followed by a slight clunk noise. To me, this suggests a trapdoor in the floor of the turbolift, and if you combine the rocket boot scene in the turbolift shaft from
STV:TFF, there should be ladder access up/down the turbolift shaft even in the TOS era. I also believe there is a trapdoor in the ceiling of the turbolift in all eras (as scene in TNG), too. When Khan locks all the exits off the bridge, he not only locked the turbolift door, but just in case they somehow force open that door to get to trapdoor, he also locked the trapdoor(s), too.
I'm not discounting a maintenance access behind the bridge consoles (probably accessed by an "environmental engineering personnel only" ladder from below

), but this is never suggested on screen, rather we see all maintenance and repair of bridge consoles from the front as seen in WNMHGB, BOT and WMFA.
YMMV
