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Unfortunately I haven't yet found a way to jump in between of those two goombas before the second one exits the tunnel.
However, I verified that it's possible to stomp them in a tunnel. It can even give Mario a forward boost due to getting inside the wall for a moment.
(This is the second time you catch me violating my own guidelines at this game - not drooling enough.)
EDIT: I updated the submission actually twice. The second time I chose to go through this little tunnel over here:

In the second part, shown in the second image, it's not possible. There is not enough room to reach the second pipe without delay, going under isn't a viable choice either, because then you can't reach the third pipe without delay.
EDIT: Forget the preceding parts in this message. I was wrong!
Edit 4: I found a swim of death:
