That so much water is pressing upwards and has not already found its way into the wall or over the floor into another room (where is the shower located?) rather suggests that the waterproofing is present and holding. But that does not change the necessary measure, because a cavity where water can accumulate over a long time and cannot dry out must not exist.
It is also interesting to ask how the area outside the shower was waterproofed. It is good if the shower is well sealed underneath and the water follows the slope to the drain there... the slope does not seem to be fully present in the substructure here, and if things go badly, water runs under the tiles into non-waterproofed areas. If there is a cavity under the tiles, we no longer need to discuss the question of whether it can be solved without destruction. However, the expert should be able to detect the cavity using ultrasound.