You got home okay and the tube did not blow out. So your choice worked fine this time.
The other option is that it blew out as a sudden puncture immediately loosing all pressure and dropping your rim on the road surface at your current speed.
If that happened on the flat and straight you'd probably stop safely.
Had it blown on a descent, or while doing any kind of turn then you're probably going to hit the deck as the wheel suddenly wipes out from under you due to immediate loss of traction.
I think you made a good call to swap tube.
If it were me I would also have "booted" the area by inserting something thin but resistant, to help prevent the tube from herniating through the hole.
Common items are a small-denomination note of your currency, or a empty gel wrapper (though make sure its as clean as you can get it, guess how I learned that!)
I generally have a plastic clipseal coin-bag used by banks to hold $10 in change, these work quite well wrapped around the tube in that one spot.
Last resort if you have nothing else is any roadside trash that is a flexible plastic. Segments cut from aluminium cans are not suitable. Single-ply cardboard can help but won't survive any water.
There are proper commercial boot products one can buy and carry for this purpose, though I'd rather use the plastic bag I happen to carry to protect each spare tube.
I would suspect that tyre is dead now. However it appears to have a lot of tread on it still, so it may be worth attempting a repair then evaluate.
- Clean the inside of those flaps, and try to abraide them, like you would a tube before patching.
- Apply vulc. fluid, and flex the tyre to keep the gash OPEN for about five minutes.
- After that, flatten the tyre out to stick the flaps down. Clamp it there for a while, and then roller it hard to try and compress it all together. Let it rest overnight in the clamp.
- Next day, find one of those horrid thick tube repair patches that everyone seems to have but not use. Patch the inside of the tyre, like you would a tube. If the vulcanising fluid doesn't seem to work on the inside of the tyre, you can use superglue instead.
The point of this is to provide a permanent boot across the slash.
Once that's all done, try refitting your tube and tyre to the rim and reinflate. With the tube at normal riding pressure, examine the repair and make a decision.
If the repair looks okay, ride it. If it doesn't, you're out some time, a patch and some glue but you could save yourself a new tyre.
If you're half-way, then a repaired tyre like this can live out its life on a trainer where a blowout is not going to strand you miles from home.
