Looking at your photo, is the membrane actually torn? It looks like it's just buckled up due to the membrane being loose or stretched at that spot. What does that spot look like on the outside when the slide is extended? Is it a true tear? If it is a true tear then it will continue ripping when the slide is opened and closed. If it's just a ripple and not a tear, it will probably just keep rubbing and rippling more as it continues to stretch under the pressure of the slide frame.
Also, if it was actually a rip, I would expect to see ragged edges along the tear line and one edge flipped upside down, not rolled like it is.
It it is actually torn, then Eterna bond tape is your best choice unless you replace the entire membrane.