<p>I'm not sure about the certain time of the <img alt="" src="https://vignette.wikia.nocookie.net/tibia/images/3/33/Strange_Vortex_%28Teleporter%29.gif/revision/latest?cb=20131215193152&path-prefix=en" style="height:32px; width:32px"> <strong>Strange Vortex</strong> disappear, but from my reminds I believe it takes like 1 - 2 min, they are not are actives for so long.</p><p>But what I'm sure is that when you pass over them they will teleport you into another area with around<strong> 10 <img alt="" src="https://vignette.wikia.nocookie.net/tibia/images/4/46/Nightmare_of_Gaz%27haragoth.gif/revision/latest?cb=20131208025358&path-prefix=en" style="height:64px; width:64px"> Nightmare of Gaz'haragoth.</strong></p><p>The best you can do is run to the south into another teleport to go back to stairs.</p>stairs because thoses creatures have instanr respawn, after you killed them, they spawn again in a moment.</p>