96 Cherokee Central Locking

Hi,

I've been caught out by the central locking on my 96 Jeep Cherokee.
If you unlock with the key fob, then only open the tail door, it
centrally locks again after about 30 seconds (Scenario was the dog
refushed to jump in the back, I put my keys down and lifted her in,
closed the tail and bingo, it centrally locked! Keys and dog trapped
inside). Pretty dumb of me I know but I would like to disable the
'feature'.

Anyone know if there is a way I can do it or is it a dealer
modification?

Also, do most Cherokee's slip out at the back when going round
a dampish round-about on the throttle?

Thanks,

Rob