Two directions at once?

More about DNA uptake:

Provided there’s enough space in the secretin pore, there’s no reason why the continuing-to-pull mechanism can’t act on both sides of the loop. This is especially true if, once the DNA has gotten started, the pilus doesn’t need to protrude through the pore but can just pull from within the periplasm, leaving the channel of the pore unblocked so DNA can move through it. The pore is easily wide enough for two double-stranded DNAs to pass through, and the non-specific binding between pilus and DNA that must be transmitting the pulling force can act on both DNAs at once, if they’re binding to different sides of the pilus.