In some cases, when the destoy method of 'Tip' calls the off() function on '$breathing', even if this one is not defined. To fix this error, we check that '$breathing' is not 'undefined' before calling off() on it.
In some cases, when the destoy method of 'Tip' calls the off() function on '$breathing', even if this one is not defined. To fix this error, we check that '$breathing' is not 'undefined' before calling off() on it.