Disembarking a surrounded Starweaver

My Cult of Red Grief Reavers (2 units of 4) charged and surrounded a limping Starweaver. They killed it. The Troupe inside disembarked on the other side of my Reavers because they “move through models” due to their flip belts.

So I guess my question(s):

A) Was this the legal way for disembarking a destroyed transport.
B) against Harlies, can we notsurround and destroy units embark on transports when the transport dies?

Thanks.

Any unit can be placed on the other side of your models when disembarking as long as all of the models are within 3" of the transport and not within 1" of any enemy models.

ok So to prevent them disembarking:
A) go in perpendicular to the transport since reavers are about 3”.
B) make sure opponent disembarks his units BEFORE removing the destroyed transport, (which is not what he did).

I hate their 4+ invul which he made a ton of magnificently.

Strictly only the Reaver bases count, so the length doesn't help. You need quite a few models to surround a transport such that there is no space within 3" to put part of a base into. They do need to disembark before removing the vehicle though.

: bummer.

Thanks y’all.