Complex sentence: Suddenly Grisham enters the room surprised to see her but he remembers the bargain about Enrique and his ardour is aroused and difficult for Tessa to cool when she is saved by an explosion from Dr Helm's office.
Split into simpler sentences: Suddenly Grisham enters the room surprised to see her, but he remembers the bargain about Enrique and his ardour is aroused and difficult for Tessa to cool. Then she is saved by an explosion from Dr Helm's office.