[rob74]

Strange, I have never heard of a separate escape tunnel for a tram tunnel. Even German U-Bahn/S-Bahn (which I am most familiar with) tunnels usually just have a walkway beside the tracks that leads to the next station or emergency exit. But I guess that also depends on length between possible stations/exits, or it's due to newer regulations, or maybe it was a "mixed calculation" ("if we build a separate tunnel, it's more expensive, but it can also be used as a bike/pedestrian tunnel").

[usrusr]

Subway tunnels usually aren't that far from the surface, even those that dive/rise between stops. So they just dot in a few emergency stairs to the surface if stops are too far apart. This tram tunnel however apparently is a shortcut through some mountain (because otherwise, the bike sibling wouldn't make much difference), so the emergency exit problem isn't easily solved by digging vertically.

[doikor]

The problem here is similar to underwater tunnels. Making an emergency exit straight up is not possible or too expensive.

In this case it is too expensive/unpractical as you would have to dig several hundred meters up a mountain. Also a tunnel going sideways is easier for those who can not walk. And this long stairs up could be a problem even to those who can walk.

For those who don’t know the tunnels goes through a 477m high mountain/hill and both ends are roughly at sea level.

[bombcar]

It depends on the length of the tunnel, the traffic in the tunnel, and various other requirements.

Older tunnels the "walk away from the dead train" option was heavily used; but more often now they try to deal with "get away from the horribly burning dead train that will suffocate everyone".