In the Maliki Madhhab, do excuses that arise beyond one’s physical control break wud

No, they do not. One is considered to be a person with an excuse (ma'zur) at that very moment, and one can continue the salat.
Samawi reasons, that is, things that arise beyond one's physical control, do not nullify wudu' in the Maliki Madhhab. For instance, while one is performing salat, if one's diarrhea comes out or if blood issues from one's boil or wound or if pus goes out through one's ears or if one's body emits worms through one's anus or if drops of urine leak out from a prostate sufferer or if chronic discharge is released from the vagina or if blood is discharged from hemorrhoids or if there is involuntary emission of wind from the anus (inability to prevent wind from coming out) or if one vomits substances to an extent that it amounts to a mouthful, none of them nullifies wudu' in the Maliki Madhhab because they happen outside one's physical control. As they do not nullify one's wudu', one can continue one's salat. However, if a knife cuts one's foot and it bleeds, it breaks one's wudu' because it is not an excuse that occurs outside one's control. But thereafter, because one's foot has developed a wound, the blood or pus issuing from it does not nullify one's wudu' anymore. Such excuses as draining of a mature boil, bleeding of a nose for no reason at all, urinary incontinence, and being unable to prevent diarrhea from coming out are all involuntary excuses, and they do not break the wudu' of a person who normally follows the Hanafi Madhhab but imitates the Maliki Madhhab because of such an excuse. If the lip and hands chap and bleed because of cold weather, this situation does not nullify the wudu' of a person imitating the Maliki Madhhab. In other words, excuses that occur beyond one's physical control do not break one's wudu'.