It is not understandable why she didn’t use the mobile phone to call Gerald or the group or, even simpler, that she didn’t walk out on the balcony from where she could be perfectly heard by the members of the group.
I think we can now reveal what we believe her reason was for the above. A phone call as well as shouting from the balcony would have put a finger on the actual time of her first alert. This could not be allowed since the body would have still to be removed and an official alert at that time might have alerted unwanted help in the "search".
That is why she most probably went to the Tapas bar and informed the table more quietly without alerting the staff and other guests and only much later shouted it from the rooftops erm... the balcony to place the timing of the alert to a later time.