I'm trying to make a (protoss) computer load a shuttle with zealots and then drop them on the player's tanks in siege mode. The problem is : after having applied the "Enter Transport" script, the loaded shuttle starts to move towards the tanks (as I asked it to), but also starts unloading its zealots immediately (and this surprises me !).

I haven't use the "Exit Transport" script in my triggers yet, so how could the shuttle unload its content ?

If you just want to keep units in the transport, use a neutral player, rather than an actual computer. Computers don't keep units in transports, since that would be stupid. Why have the unit inside when it could be out fighting?

You're going to have to use a virtual shuttle. When the zeals are brought to shuttle, play the sound, remove/move the zeals, order shuttle, then create/move the zeals under shuttle.

This.

Although at times the virtual shuttle can be impractical, it is a very useful system nonetheless.