During her convalescence at the Queen Elizabeth Hospital, Malala has been working hard at the gym and with a physiotherapist to get her arms and legs working properly again. As a reward for all the progress she's made, Malala is taken on a trip by two hospital staff to the Birmingham Botanical Gardens. The hospital staff know that Malala loves nature, so they figure that visiting the Gardens will assist her recovery.
In allowing Malala to go on an outdoor excursion, the hospital administrators need to take precautions to ensure her safety. She is, after all, a victim of terrorism and still needs to be protected from those who would harm her. This means that Malala and those going accompanying her to the Botanical Gardens shouldn't attract too much attention during their visit. For this reason, Malala's mother can go with her, but not her father, as he would be too easily recognized on account of his regular appearances in the media.