I've had this idea for quite some time now..

But basically, what if there was an agent that had an ultimate or ability (if you think it's not as broken) which lets them dig a short tunnel. Like a lil' mole rat.

Since they seem like a sentinel, their other abilities would be trips and such.

Some functions and nerfs...

1. The tunnel is very obvious with debris coming out of it (or better yet, it's indicated where you dug on the map for everyone) and some controllers can see the tunnel with their smoke placement screen.
2. You can only make tunnels that have an exit.
3. The tunnel will collapse after a while and anyone inside as it collapses will die. You have time to escape as it shakes violently when it's about to collapse.
4. A max of 15 meters for a tunnel.
5. You can't use it pre-round and it takes a while to dig (on top of the voice line if it's an ultimate).
6. The tunnel can be collapsed manually by shooting at it, a lot.

A friend looked at this idea and said it reminded him of puncturing holes in RS6. That would be really broken for this type of game so I added some of those nerfs to avoid unfair off angles and instead an off angle that is obvious.

I would say this ability would be used for quicker rotations, making it difficult to retake and such.

But what do you think? If there are agents that can place things on the map, what if there were ones that could remove or change things? Do you think there are things that could change to make this guy balanced or viable? Or is this idea stupid in general?