Check my tunneling arrays
R, 47 bytes



function(v,a=v[v&gt;0],b=sort(a))all(v[a]==b&amp;a!=b)


Try it online!



Unrolled code and explanation :

f=
function(v){          # v vector of tunnel indexes (1-based) or values &lt;= 0

  a = v[v&gt;0]          # get the tunnel positions

  b = sort(a)         # sort the tunnel positions ascending

  c1 = v[a]==b        # get the values of 'v' at positions 'a'
                      # and check if they're equal to the sorted positions 'b'
                      # (element-wise, returns a vector of TRUE/FALSE)

  c2 = a != b         # check if positions 'a' are different from sorted positions 'b' 
                      # (to exclude tunnels pointing to themselves, element-wise,
                      #  returns a vector of TRUE/FALSE)

  all(c1 &amp; c2)        # if all logical conditions 'c1' and 'c2' are TRUE then
                      # returns TRUE otherwise FALSE
}