Its being ejected by a supermassive black hole. Maybe some of these planets are still probably in orbit around their parent stars.
Probably not. Be lucky if the tidal forces didn't tear the planet asunder, much less let its home star keep hold of it. The reason Saturn's rings don't coalesce into moons is tidal forces, the reason the material left in the asteroid belt doesn't coalesce into a planet is tidal disruption by Jupiter. Image what the tidal forces around a black hold must be like.
It's like a game of snap-the-whip with the outboard body being tossed into the void of intergalactic space, while inboard member is trapped in orbit around the black hole. Normally, when two bodies that are not gravitationally bound interact gravitationally, their orbits will be hyperboles, with each object being deflected from its original trajectory, but never encountering each other ever again. When three or more bodies are involved, things change. For example, when a comet comes near Jupiter on its path away from the sun, one of two things can happen. If it encounters Jupiter so that it passes behind Jupiter in his orbit, the comet will be accelerated by Jupiter and tossed into a higher orbit (while slightly decelerating Jupiter and lowering his orbit). In some cases the acceleration is enough to toss the comet completely out of the solar system. If the comet passes in front of Jupiter in his orbit, the comet will be retarded, and Jupiter will increase his orbital energy. In the case of Shoemaker-Levy 9, the comet was so retarded in a 1968 pass that it was captured by Jupiter and remained in a highly elliptical orbit around Jupiter until 1994, when this unstable orbit was perturbed (possibly by one of Jupiter's moons) just enough that it collided with planet. The shredding of Shoemaker-Levy into pieces was caused by tidal forces long before the collision.
When a double star, or a planetary system (systems which are already gravitationally bound) encounter a black hole, the outcome would, it seems to me, depend on whether or not the direction of their orbit around the black hole is in the direction of their orbit around each other, or counter to it. If it is in the same direction, tidal forces will tend to tear the two asunder, stressing and possibly breaking their gravitational bond. Depending on the original trajectory and mutual orbit, one of the bodies may be tossed out to the galaxy, "by the other body", in the same way that Jupiter tosses a comet out of the solar system, and the other body will lose kinetic energy and may even become gravitationally bound to black hole.
If on the other hand, the two were orbiting opposite the direction of their encounter with the black hole, tidal forces would bind them even more firmly, at least initially, until they reached the point in their hyperbolic orbit about the black hole of closest approach, after which tidal forces would pull them apart until as they left the influence of the black hole, their orbital state would be stored to what it had been before they encountered the black hole.
That's racist!