Probably the child safety locks are turned on
is the reason that the doors will not open from the inside.
You have to open the door to turn the child safety
switch on or off.
Look in the owners manual for the location of the manual switch.
It is not very common that both rear doors will not open from
the outside at the same time. There is a rod on each latch that
connects to the outside door handle. This rod may have come
dis-connected from the handle.
Lowering the window might gain some access to be able to
trip or pull something on the latch that will permit the door to open.
It is not very easy to remove the inside door panel with the door closed.

If you do get the door open you still need to check out what went wrong.

The door lock part may have failed and the latch is in the locked position.
Do the rear door lock knobs go up and down?
If they do not, open the 5th door. In the left rear coner area is a side
panel.
Remove panel. you will see fuses and relays. Remove fuse number1 in the
upper back corner for about 10 seconds and replace.
Now see if the door locks work.
If this made the door locks work, the REM or Rear Electric Module
went to sleep. This woke it up. This will also work for a non opening
gas door. There is a Volvo reload to keep the REM from going to sleep.

Let us know,

BD
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