Ust Natha and Mother ardulace

Arthas

Was the matron mother plotting to besiege suldanesselar to help Irenicus ?

Or did irenicus give the eggs just to make her help him?

These two things are not clear to me.

jsaving

Neither cared about the other at all, but each believed the other could be used to advance their objectives.

Ardulace had wanted to take Suldanesselar for a long time but could not get past the silver dragon to do so. Irenicus couldn't enter Suldanesselar while under elven control but had no problem getting past the silver dragon. The eggs were a win-win, allowing Ardulace to take the city which then enabled Irenicus to reach the Tree.