Must I repeat my ablution if a slight flatus is expelled during ablution, knowing that I suffer from excessive flatulence and urinary incontinence ( سلس الريح)? And is it permissible for me to perform ablution five minutes before the Adhan so that I can go early to the mosque?

We ask Allah to hasten our brother’s recovery, and we appreciate his eagerness to go to the mosque early. If the flatulence is continuous, such that it does not stop for a period long enough for you to perform purification (wudu) and prayer, then you fall under the ruling of one afflicted with سلس (incontinence). You must perform wudu for each prayer after its time has begun, and you may pray as much as you wish even if flatulence occurs, and you are not required to repeat the wudu. It is not valid to perform wudu before the time of prayer begins. However, if the flatulence stops for a period sufficient for purification and prayer, then you must pray during that time, even if it leads to missing the congregational prayer.