Once unplugged, conduct a visual inspection of the coil terminal connecters; i.e., male/blades in the coil port and female/wire terminal ends in the receptacle housing. From my experience, the blades in the coil were visibly degraded from arcing that had occurred, which is a clue that the receptacle housing is not staying fully plugged in. The coil then fails to fire. The suspect coil was a throwaway at that point.

Would recommend acquiring a new receptacle housing from Volvo, repinning it, and finish the job in #4 cylinder with a new coil. Then, you're confident all contacts are good.

Some with more patience than I can use small screwdrivers to release the barbs that hold the wire terminals inside the receptacle housing, and then pull out the wires. The referenced terminal extractor tool makes a much easier task of it IMHO.