Despite the chill that he felt at the tragic sight of Azsa and Hedi Curry, Sheyan's worries were actually completely unfounded. This was because he already had one of the most horrifying parasites possible inside his body -- the 'Stairway of the Sun'. It was just that the 'Stairway of the Sun' had completely lost its own consciousness, so it would not hurt Sheyan.
If the Slaad planted its fertilised eggs into Sheyan, nothing would come of it. The tendrils of the 'Stairway of the Sun', which grew along Sheyan's blood vessels, would eat the fertilised eggs for dessert. The tiny fertilised eggs could never hope to compete with the powerful 'Stairway of the Sun'!