Is there any connection between feeding times and/or bowel movements and the screaming/tensing as it could also just be gas and upset stomach and especially if she is doing well at the traditional times that kids cry like dropoffs and naps.

Ask the mom if she has had any issues at home with crying and tensing or if she was colicy/gassy as a newborn.

During those times you could try picking her up and draping a blanket - something snuggly and fairly heavy like an afghan or quilt to give some weight and then hold her close till she settles. Gradually loosen the blanket till she is fine without being covered and repeat as needed.