Hit the marker to begin your journey into the transinfinite.
Head for the cargo depot, as the two mythologically named protagonists verbally spar. When you arrive, you'll be given an objective to seal the rifts, and a timer with four and a half minutes. Rift sealing does not add any seconds to the clock, so move with purpose.
You're going need some altitude for the first one, so look for the giant stack of crates near the indicated building.
Up top find the first rift. You no longer need to interact with them to seal them, just moving in close is enough.
Follow your locator scan from rift to rift. Do use your locator scan each time- sometimes you can see multiple rifts around you, but the game wants them sealed in a particular order.
The last one is a warehouse, but you'll discover there are more spawning amongst the container crates. Dash over.
Clear the container rifts (keeping your eye out for the multiples crystal shards and loot boxes squirreled away here). When done, cross the street and ride the indicated platform up to roof level. Note that the first rift in this sequence is actually on the level below you.
There are a number of swarmtroopers active here, but you're on the clock. Just make straight for the rifts, keeping an eye on your locator for changes in altitude. The final rift will be on a neighboring rooftop.
Snag any crystals or loot here before closing the rift, as completing this objective will close out the mission, and whisk you back down to the streets.