If he is on about a real engine failure, it is impossible to get into vortex ring.
I think what he may be refering to is when carrying out a PFL. It is strongly advisable to get forward speed on prior to raising the collective for the over shoot.
When carrying out a constant attitude EOL (which is pretty much vertical or at least with low G/S), I would suggest it is impossible to get into vortex ring!
Remember the old vortex ring state 'triangle of fire'. Low airspeed, high RoD, power on. Take one of those factors away and you remove the risk of the state.
And I'm sure that Nick will add that from low level, getting into full Vortex ring is very hard! It takes quite a bit of height for it to develop into full blown vrs.