[neovialogistics]

Very basic explanation here, you will only need the visualization powers of high school physics:

Most gas that approaches a black hole does a gravitational slingshot and escapes.

This paper proves that the majority of escape trajectories eventually return to the black hole (effectively multiple attempts at getting absorbed). This has long been an assumption for running low-fidelity statistical modeling but it is now proven that the assumption is valid and that therefore the models are (mostly) valid.

[Blikkentrekker]

In that case how is it a slingshot and a very eccentric orbit?